How a Thermostat Works in the E46 - How to Diagnose a Broken Thermostat

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You can check temp from your instrument cluster. Search for KZbin videos on "E46 temperature instrument cluster", E46:
1.) Turn car on with engine running.
2.) Hold the instrument cluster button for 10 seconds until 1.00 appears, release and press repeatedly until you get to "19 unlock", then leave it there for a few seconds to select it.
3.). Now press the button repeatedly until you get to the function you want.
7 - Coolant Temperature readout.
9 - Battery voltage readout.
4 - Fuel consumption (press the button to cycle to different readouts, l/h, l/100kms, etc)
2 - Instrument cluster test
How I removed thermostat:
1.) Drive the car onto a ramp.
2.) Remove the push pin center fasteners/philips screws from the lower engine protection pan.
3.) Drain the coolant from the radiator drain screw, open bleed screw and cap to increase flow. Optional: Drain the coolant from the engine block by removing the 13mm bolt on the block below cylinder #2(2nd from the front, rear cylinder is #6 closest to the rear of the car), MAKE sure you close the all the other bleed screws and cap before doing this, so that the coolant flows slowly, once the 13mm bolt is out, then you can open the top bleed screw by the radiator cap to increase flow.
4.) Remove the plastic intake duct to the filter box.
5.) Use a 32mm open end wrench and turn clockwise on the fan nut, if you don't have a fan clutch bar to hold it steady, use a hammer to hit the wrench in the clockwise position to unlock the nut, it should come loose with a medium hammer hit, if it is siezed on there, you'll need a clutch bar to hold it steady. You can retighten the same way.
6.) Remove all the bolts for the thermostat, remove the hoses for the thermostat by pulling the locking pins, a flat head can be used to pry the hoses away from the thermostat.(The plastic will break if it's brittle).
7.) Clean the surface with a flat scraper, be careful of the sharp edges of the aluminum block.
8.) Use an RTV silicone meant for water pumps, and create a bead along the outside of the new gasket on the new thermostat. These thermostats have been known to leak due to a poor rubber gasket(BMW should us a high quality silicone gasket), so the RTV silicone is a must if you don't want a leak.
9.) Install everything as you removed it, except the radiator cap and top bleed screw, leave those loose since you'll be adding coolant.
10.) With the engine off, fill the system with approximately 8.5L of 50/50 antifreeze. Any antifreeze meant for new engines(aluminum) blocks will do. To avoid a mess, wrap a rag around the bleed screw and radiator fill port to catch radiator fluid.
11.) Turn on the engine, the coolant that was full will now be drained by the water pump, top up the coolant once again.
12.) Drive the car down from the ramps, put the cabin heater on high, fan on high. Rev the engine a bit(~3500RPM max, or the radiator fluid will splash out of the fill port), pump it a few times to move the air out from the system to the radiator cap/bleed screw location. Top up the coolant once again as required.
13.) Give it 5 minutes to heat up and open the thermostat, rev the engine a bit and add coolant as needed.
14.) Once coolant starts to leak from the bleed screw, close it. Now the engine should be warm, the thermostat should be open, and the air bubbles should be out of the system. Now the system should be full of fluid, and have no air bubbles.
15.) Install the radiator cap, drive the vehicle around the block a few times, getting it revved up to about 4500RPM should get the air bubbles out, nothing crazy like 6500RPM is required.
16.) Park the car, and let it cool for at least 2 hours, then open the bleed screw beside radiator cap again, it should release air, as soon as fluid comes out close it, and your system should operate properly.
Thank you for all your support and views!

[@fjwong7337]

David Sunshine: Excellent video and tutorial in explaining how thermostat works! I also would like to compliment you for your comprehensive and tireless answering of specific questions. Thank you!

[@DavidSunshine]

Thank you Frank! I appreciate it! I enjoy this stuff and hope everyone else does too. The pleasure is mine!

[@butchoygonzales916]

Well explained, very nice! 👍🏼 thank you!

[@monregranvillealexander287]

Thank you for this amazing explanation brother. Mine took about 25min to remove and replace today. Thanx to the electric fan and easy to remove clips.

[@ab8jp]

I actually thought that this connection was a temp sensor. Very informative! Thank you!!!

[@DavidSunshine]

Haha, that would be cool, but it's just the heater. The temp sensor is down low on the radiator pipe inlet(or outlet, I forgot). You're welcome! Glad you liked it.

[@markalvinchow6973]

Excellent Work My Friend ! Sydney Australia .

[@DavidSunshine]

Thank you!

[@DarkBattleWolf1337]

Excellent video and good info. Thank you! :)

[@DavidSunshine]

Thanks! Glad you enjoyed the video! The pleasure is mine! Cheers, David.

[@leonchang9692]

Very informative and knowledgeable video. I'm about to replace the stuck open thermostat tomorrow. Please make more videos in the future thanks!

[@DavidSunshine]

Thanks. Glad you liked it. It's a pretty easy process. Be careful at the thermostat opening of the engine block. It was sharp and cut my hand like a knife! Cheers, David.

[@williamfigueroa6662]

tank you amigo nice video, now I now how check my thermostat. God bless you.

[@DavidSunshine]

You're welcome! Glad I could help. Cheers, David.

[@tspark1071]

Cool and useful. My e46 it shows about 89~94. In case of e90 the temp varies around 105~112.

[@renatomartinez8096]

excellent video.good on the details.

[@DavidSunshine]

Renato Martinez Thanks man! Glad you like it. Cheers, David.

[@bethells86]

Wow, well done!!

[@masterplanz3938]

Great video! Thanks for sharing!!

[@DavidSunshine]

You're welcome! Hope it helped! Cheers, David.

[@anthonymasters07]

Very helpful. Thx a million!

[@DavidSunshine]

Glad it helped! You're welcome!

[@robertmnoyan9465]

Thanks for video, very useful.

[@DavidSunshine]

You're welcome! Glad to help!

[@tobiasranzinger]

you don't need obd(II) to get the exact temperature. just go in the undermenu on your bordcomputer, test 19, loff, and then test 7. in this test the exact temperature of your water is shown on the bordcomputer. best regards from bavaria ;)

[@DavidSunshine]

That's awesome, thanks for the tip! I'm gonna have to try that out. Cheers, David.

[@hugostiglitz5976]

@@DavidSunshine you think the heater/ plug would have anything to do with the thermostat not opening? I've gone through 2 new ones, and same thing.

[@niewissen9912]

@@DavidSunshine menu 19 you have to put the sum of the last 5 of your vin then it will unlock all in the menu and can see everything. Water temp. Fuel temp, oil temp ect. Lots of stuff in there

[@DavidSunshine]

@@niewissen9912 Nice! Great advice! Ya I used that in a pinch when my serpentine belt snapped on the highway. Had to keep punching it in to check my temp so I wouldn't overheat the engine. Finally drove it off the highway after a few drive-air cool-drive cycles. Life saver, those cluster menu options. I put the instructions of how to use the 19 menus on the description for anyone who's interested as well. I don't think my E46 needed the unlock code, it probably got unlocked for good the first time it was plugged in maybe? For an E70 you gotta plug it in every time lol, sucks when it's like 20+ clicks. Cheers! David.

[@BirdogEd]

Excellent job! 😎🇩🇪🚙

[@DavidSunshine]

Thanks man!

[@tamargueira1]

Thank you! for the great video

[@DavidSunshine]

You're welcome! Glad you enjoyed.

[@rafaelalvarez.exitos]

Thank you my friend

[@IvanPandev-rv4bv]

Great info, thank you

[@DavidSunshine]

My pleasure! Have a great day!

[@saljudeh]

Thank you. Best vid ever

[@DavidSunshine]

Thanks man!

[@BimmerFix]

This was one of the best videos. Tested new thermostat with 12v and 1 amp, it opened after a few minutes. Tested old thermostat with 12v for half an hour, it didnt move. Thermostat was dead, so when idling my temperature was ok, but when driving i was badly overheating.

[@DavidSunshine]

Thank you! Glad you enjoyed the video! It was fun playing around with the thermostat and documenting my findings. Good job fixing the overheating issues! Happy driving! Cheers, David

[@BimmerFix]

@DavidSunshine the one thing I didn't realize is that the thermostat comes out of the housing! Basically you can swap the thermostat into an aluminum housing!

[@DavidSunshine]

@@BimmerFix Dang that's awesome! Would be a cool upgrade for sure. I sold my 325ci but I miss it. I see it driving around town sometimes. Cheers! David

[@contrerasmcr100]

savage, thanks for the info, I'm replacing mine cause is ruining cold on the freeway, the faster I go the lower it goes.

[@DavidSunshine]

Miguel Contreras You're welcome! Ya, had the exact same problem. I guess after about 10 years it starts to fail, it's funny cuz I think it broke in the summer, the winter before it was fine, then it started to get cold and I got no heat on the highway. Taking the fan off is tricky, but if you hammer the wrench it will loosen up, you don't really need the bar to hold the fan still, just use the inertia of the shaft and other pulleys. Cheers, David.

[@fjwong7337]

David: Just like you and your readers to know that my 2003 330i (purchased in 2003 with about 20,000 miles) just passed 100,000 (used to be wife's car)! Thermostat never replaced! So apparently it has a life of more than 10 years; car always parked inside garage, in Portland Oregon. Bought a thermostat Wahler (box said Made in Germany with the BorgWarner marking) in 2017, not installed. It cost less than $50 from Amazon. Still exploring the mechanical aspects (draining the coolants and removing the fan and shroud a big adventure for me), hence coming across your excellent video. Yours gave me more confidence! Just re-built the DISA valve with an aluminum flapper and titanium rod/screw, having found the original spent flapper pin (metal) separated from its perch and dropped inside the manifold, almost had a heart attack! Luckily it didn't get sucked into the nether! Also cleaned the idle control valve, and flushed the throttle plate. Bimmer is now as responsive as it was NEW! In conjunction with the thermostat replacement, will also do the VANOS o-ring and seal repair.

[@DavidSunshine]

Hi Frank! That's great. Good it ran that long. Mine was running fine until about 12 years old, was 2005 and I think the thermostat stopped closing in 2017, I put cardboard in the front so it could warm up on the hwy, until I got around to replacing it. It's not hard at all, with all the KZbin videos out there, I was able to replace it easily enough. I had to replace the starter because the battery was getting low and I kept using it, the weak battery must have left too much carbon on the commutator of the starter. When I replaced the starter I had to take out the throttle body and cleaned it too. I also did the DESA valve as preventative maintenance, it was ok, but better safe than sorry. It's game over once the engine eats the metal pin! BMWs are a pleasure to work on, hope you enjoy swapping out the thermostat! Cheers, David.

[@fjwong7337]

@@DavidSunshine love your creativity and bravery. We have come a long way! My other car, a 1999 Honda CR-V from new, manual is approaching 400,000. Still drives smooth.

[@DavidSunshine]

@@fjwong7337 Amazing! That's Honda longevity for you! I've heard of civics getting over 500,000kms, that's insane. BMWs can get up there. But complicated systems require complicated fixes. VANOS is one of those. I got rid of my 325 at about 146,000kms though, so didn't have to do the VANOS. In time I'll have to pay some attention to it in my X5 though. I guess you're gonna do that soon too. Good luck and hope you enjoy it! Looks like a fun job to do. Cheers! David.

[@gentlemen1020]

Very impressive meticulous explanation.

[@DavidSunshine]

Hope it helped!! It's a pretty simple system once you understand it, the bleeding process can be tricky, but there are many videos and instructions on how to do that. Cheers! David.

[@AndyNav1]

Thanks again. Appreciate your comment.

[@rocketlochet]

Great video, your'e best

[@smooveking773]

WOW GREAT VIDEO

[@DavidSunshine]

Thank you! Glad you think so! Cheers, David.

[@bmwmpower326]

Profesionel video Thanks a lot bro

[@DavidSunshine]

Thanks! You're welcome! Cheers, David.

[@slammedb18a1]

Yessss, I use the same adapter with the same app! Been using it for years on all my vehicles

[@DavidSunshine]

Lol awesome! Ya it's great! I've gotten Carly too, so that I can code and do deeper diagnostics, definitely worth it if you need those extra functions. Especially battery registration for the newer BMWs. Cheers! David.

[@slammedb18a1]

@@DavidSunshine carly is next!

[@DavidSunshine]

@@slammedb18a1 nice. I recommend it. It saved me when the car battery was low and all the systems locked up and it wouldn't start again until I cleared all the codes. I've also used it to code mirrors, warnings, and other useful features. Cheers! David.

[@MJ-xm1jb]

Very informative video man! Thank you!

[@DavidSunshine]

Glad you think so!! Thank you for the positive feedback! I appreciate it.

[@sambking]

Good stuff. Very interesting. I wonder how the metal shaft gets bent simply going up and down over the course of its life? Either way great video!

[@DavidSunshine]

Thanks! Probably gets caught on 1 side over time, causing an uneven force on it, torquing it and bending it a bit. That's probably why it stopped closing in my E46, and then I was stuck with constant cooling, couldn't get heat on the highway lol. Replaced mine and it's working fine. I could have probably just taken this one out, straightened it up, polished my shaft real good, put it back in, and I'd be good to go! Cheers! David.

[@kslloyd8443]

Good Video- Who makes and where can one get the USB OBD adapter ? And the instrumentation that you included in the video do you need a special app to display that ?Thanks for the help !!!

[@DavidSunshine]

Thanks. I use the OBD II to bluetooth adapter, it doesn't have a brand name, random companies in China make them, they seem to work fine. It must be paired with an Android smart phone, and the app you must download is Torque Lite, it's free, and does everything you basically need. You can pay $6 for the Torque app if you want additional features tho. I got mine from here: tidd.ly/625a3033 Cheers, David.

[@rileynorton3761]

They are pretty damn handy for a cheap China product. My instrument cluster has died and the only way I can see my coolant temp is through the app. Without it I’d be kinda fucked, and it ended up being the thermostat the actual plug which heats the thermostat up has completely corroded and fallen off plus the stat itself is as crusty as my nans homemade bread lol. And the plastic housing pretty much broke to pieces when I was simply trying to inspect it 😑 I fucking hate plastics for critical parts in engines, like fuck off with that cheap bullshit.

[@montoyas]

thanks for an awesome explanation, yet, I would like to know your opinion, I have a 04 X5 and I do not think the thermostat has been changed. I recently did some replacement regarding the coolant system. However, every time I go on the freeway, the needle goes higher when I accelerate, but then returns to the 12oclock position when I reduce speed. No leaks, in your opinion, should I replace the thermostat? Thanks

[@DavidSunshine]

Hi Samuel! Anytime! I'm not sure what's happening there, seems kinda strange. But from my experience with BMW cooling systems, they get lots of bubbles in there and you really need to do a proper bleed procedure. Google how to do the bleed procedure for the cooling system, it says a bunch of stuff about pushing down the accel pedal to activate the pump for 10 min. I tried it on my X5 after I replaced the aux turbo coolant pump, but it didn't work. The system didn't function properly until I floored it a bunch, the high revs got the bubbles through, and it worked properly, but that's probably not the best way to do it. I suspect you introduced air to the system after your replacements. I don't think the thermostat broke after your repairs, that's too coincidental. So look into that and see if that helps. If not, you could be right, the thermostat might not be opening up fully. The thermostat is getting old, so the wax might be wearing out, might be a good time to replace. Cheers, David.

[@gringomassive6451]

Thanks for your video. So like this i can control the engine temps to be around 85c on X5 E70 without buying low temp thermostat. I actually thought it have 3 temps sensors, 2 on the thermostat housing and 1 on the radiator outlet. Thanks buddy for your informative video. I'll just get a switched temp sensor to close the circuit on 85c and force the thermostat to open and close on 80.

[@DavidSunshine]

You're welcome! That would be a good workaround to replacing the thermostat. I've been meaning to replace the pressure cap with a lower one, and thermostat with a low temp one too in my X5 with an S63, it runs hot. That's a good idea to wire it to a thermostat that activates at 85 though. I would add an interposing relay so you separate the circuits, so the original circuit can continue to feed 12V to its interposing relay, while the 85C thermostat feeds its own interposing relay, both of which can connect it to 12V, then no backfeeding will occur. I'm sure the original controller is solid state, so you don't want to hook it up to any custom circuit, it'll probably throw an error or worse, be damaged. All these new solid state controllers are so sensitive. Great idea tho! Any bimetal thermostat should do the trick. Cheers! David.

[@gringomassive6451]

@@DavidSunshine these cars with V8 runs extremely hot. And to get things worse, i live in UAE where there's no winter and temps averaging 113F°. I have a trick not to throw any DTCs, i made it when i disconnected the AC heater hoses, i kept the solenoid valve and closed the pipes, and removed the water pump and connected brake light bulb instead. No errors whatsoever. I believe it was 15W. I'll do the same with thermostat heater. I already measured the resistance when the coolant temp were 205F°, it was 158ohm. I made a relay and connected the resistance to it, and will make it to activate once the temps reach to my desire, along with the thermostat heater. Like this will not throw any codes. Thanks a lot David, you saved me a lot of hustle to open the thermostat. This way is cleaner and no coolant wasted in the process. Cheers. Faris

[@DavidSunshine]

@@gringomassive6451 Hi, wow that's hot, ya you'll benefit a lot from running cool. I live in Canada, so it's colder most of the year, which is nice on the V8. Smart idea with the bulb to pretend to be the pump! I've used a light bulb to trick the computer that the O2 sensor heater was connected too, haha. That's great it'll save the thermostat from having to come out, then you don't need to bother with the bleed procedure either, that's a mess and a pain. My pleasure! Glad I could help. Enjoy the mods! Cheers! David.

[@louis-vincentnadeau3466]

Hey thank you for this specific assistance.. i am running cold (stuck open ) on a year old thermostat .. i am presuming a mixture of different coolant and a low level from a leak could have caused it to fail so quick ?

[@DavidSunshine]

Hi, Anytime! It's strange that a one year old thermostat is stuck open. So on the highway, at high speed, the engine cools down to the point where the temp gauge goes to the left of 12 O'clock? Yup, that would mean the thermostat is stuck open. I would try testing the voltage from the plug, if it's stuck on 12V, that would explain why it's forced open. Could be a shorted MOSFET causing it to hold 12V to the thermostat, MOSFETs can fail and when they do it's a short for all 3 pins. So that could be the issue. When cold starting your engine, that plug should be giving no voltage. You could even just unplug the 12V, it's not required. The thermostat will open naturally from the hot radiator fluid. You may run a little hotter, but at least you'll know it was the plug causing a forced open. If you have air in the system, your cabin heat will be cold, but it engine will run hot, if that's the issue, all you need to do is bleed the system properly. Hope that helps and you get it fixed! If it's none of the above, then a new thermostat should fix it. Cheers, David.

[@AndyNav1]

Thank you

[@DavidSunshine]

You're welcome! Cheers, David.

[@TheHeretic435]

Good tip on testing w/ 12V. My E39 coolant temp was thru roof today. First time. I'm guessing thermostat gone bad?

[@DavidSunshine]

Could be, but usually they get stuck open, but could be stuck closed I suppose. If it's old, might as well replace it. Sometimes the expansion tank cracks, that drops the coolant and causes overheating. Check to make sure you system is still full and sealed up. Water pumps are known to go bad too, and fans, I would check it all. Cheers! David.

[@AndyNav1]

Thanks for sharing. Pulled out the thermostat out of the casing but cannot put it back on again! How did you do it. There seems to be a jump in the video at that stage. Also when I tested the thermostat in boiling water neither the existing one nor the the brand new one open. Any guidance will be much appreciated. Thanks

[@DavidSunshine]

Hi, At 4m40s I use needle nose pliers to push the spring clips back in. Helps to do it on carpet so the housing doesn't slide. Did you try hooking up 12Vdc to it? They should open like in the video. I didn't try boiling it, but that should open them too. If they aren't opening, they both could be bad? At boiling temp they should really open. I've reviewed a brand new part that was broken, BMW oem, so could happen. But try the 12V, if it don't open from that, something is wrong. Just use jumper cables and a car battery if you don't have a 12V 2A power adapter. It's not polar sensitive, it is just a resistor, so connect it and it should open in a few minutes, give it 10 to be sure. Cheers, David.

[@robjenkins3713]

Such a useful video, without all the flashy music crap adored by others. Wish I'd have noticed this yesterday before destroying what may have been a perfectly good thermostat. I have a no cooling fan problem fan on my E46 petrol 3 series and suspected the thermostat. Like a fool I believed those thermostat terminals were a switch bought on by the stat pulling back. I boiled up my old unit in a pan of water and as nothing moved I suspected it was duff. I then ripped it out the casing, only to learn nothing more. Now i see it moves under 12volts A new one was £12, so not so bad in the end. Still have the fan problem though.

[@DavidSunshine]

Thank you for the comment! That's not a bad price, and probably good to replace the thermostat anyways. It should still open but boiling it, since the wax should expand, so maybe the wax was getting old. There are a bunch of videos about the E46 cooling fan actually, I watched some out of curiosity. One user even bypassed the automatic relay and added a manual switch inside the cabin to turn it on! That's an easy fix, but not optimal since you might leave it running when it's cold or forget to turn it on when hot. Hopefully it's just your fuse or a loose connection, but this guy goes into checking codes and the DME wire. Seems like a common problem so you should be able to diagnose it with help of all the KZbinrs who have posted their tips and tricks. kzbin.info/www/bejne/jIaQdIRpn7V8b7s kzbin.info/www/bejne/iJWsc5Woo5hgaZI Good luck! Cheers! David.

[@robjenkins3713]

@@DavidSunshine Thanks for the reply David. My BMW thermosat is a slightly different shape to the one in your video but the principle would be the same. For those interested the BMW (UK) part number is 11531436042. These can be picked up new on Ebay for less than £15, but I'm wondering if theres a quality issue with these cheap copies compared to those from other car parts stores that charge around £35 - £50. My last ebay purchase only seemed to have lasted less than 2 years before failings. I applied 12 volts to the pin from my old stat yesterday and although it gets very hot it was still tight in the hole with no movement, so maybe the wax had hardened up just as you said. All this still hasn't resolved the main fan problem, so I guess I'll have to browse those videos to fit a temporary override switch until I get to the root of the problem. Seems the fan module is already fed by permanent 12 volts and is only signaled to come on from the single green and black wire from the DME. Thanks again for the guidance.

[@DavidSunshine]

@@robjenkins3713 Anytime! Ya I did find the eBay parts to be inferior to brand name parts from Napa or good online sources. Hopefully you can get it powered up with a bypass! Or troubleshoot the code or root problem. Good luck! Cheers, David.

[@notpinhead3514]

So I want to try cleaning it before I actually replace it. I'm a little confused though, is sticking the heating element of the thermostat inside and letting it heat up cleaning it or should i put it in an out while its cold? Because what you did and what your comment says is the opposite. Thank you!

[@DavidSunshine]

FrnchFriez Good question. If you heat it up and let the wax spill, like I did, that'll screw it up, cuz you're not supposed to lose wax. Just remove the shaft and try not to bend or scratch it. If it's a little bent, try to bend it back without denting it. Gotta keep it perfectly shaped. You can probably polish it with polishing compound to try and make it a mirror finish, that may help make it function better. But if it's failing, most likely the seal is bad and you've lost wax, but it's free to try so worth a shot cleaning if you got the time! Cheers, David.

[@justinlopez8879]

I bled the system and then ran the car on idle after about 2 minutes I could see bubbles start to form where the gaskets seal the thermostat to the engine and about after 5 min on the lower left corner of the thermostat steam start to come out as if it was a teapot?? Any ideas on and my temp gage reads normal. I could also smell coolant vapors... Thank you so much for your time and help man

[@DavidSunshine]

Oh, well, if the gasket there is gone, or the leak is there, it's probably 10 years old and the plastic has gotten weak and brittle, the pressure must have caused a crack. If it's that old, for sure you need a new one. Buy some RTV gasket maker and a new thermostat and replace it. Should stop your car from thinking it's tea time. When cleaning the area, be careful, there are razor sharp edges around the opening to the engine. Good luck! David.

[@AssinaturaPicazica]

I have a e46 320D 00', I notice that the temperature neadle goes to the middle after 3-5 minutes after starting the engine, the problem is that the eletrical fan doesnt kick in, even If I do a big trip. Already check the coolant sensor (very dificult to get to it) and repleaced it. Might be the module attach to the back of the fan, but I dont know how to know if its that (costs about 200€ here in Portugal) Any help would be highly appreciated

[@DavidSunshine]

Picazica Hi, I haven't had that issue, but there are a bunch of KZbin videos that help diagnose it, seems like lots of people have put in switches instead of letting the car run the fan, I don't like that, I'd rather fix the actual problem lol. Is your coolant overheating? Check the temp using the digital read out or the OBD 2 reader. If it's hot and the fan still not running, the temp sensor is good, troubleshoot the fuse, 12v at the fan, relay, the fan itself, if all that works, then it should run when hot, if not, maybe the ECM output is fried, and that's why people have added a switch. I would personally add a bimetallic switch somewhere, tape that to the radiator somewhere with thermal grease, and have that operate a relay. When it's at 85C I would run the fan, it just automates the activation. Check temperature kzbin.info/www/bejne/rZuupWOQhqeJaLc Fix overheating kzbin.info/www/bejne/oXS7hXl4js57Z7M Hope that helps. Cheers! David.

[@amy40c]

Thank you for clear explanation! I have my temp gauge on dashboard showing max temp as soon as I turn ignition to ON position even if the car is cold in the morning. I have changed temp sensor and tested all wires for that sensor, but still have the same problem. My engine is not overheating when I drive it, but I think it is under working temperature. Can thermostat be a problem here? Im not so sure because thermostat is not connected to the temp gauge on my dashboard which is showing wrong temp...

[@DavidSunshine]

Hi, that seems weird. The thermostat doesn't read the temp so that's not it, your thermostat may be fine. You'll want to read the temp with the obdii reader and torque, or just read it from the cluster. I don't have a video showing how to do it, but there are plenty online, check it out here. kzbin.info/www/bejne/rZuupWOQhqeJaLc Search for more if you want. You can also read voltage, gas mileage (I think that's 4) and all that, coolant temp is 7. If that digital temp read out is also high, you probably have an issue with the sensor, if this is the case, it's hard to troubleshoot, but I'm sure you can get it figured out. One possible place that causes electrical issues is the junction box or fuse box in some BMWs. Since all the connectors don't have dielectric grease on them, they corrode and cause issues, intermittent connections or high resistance, and open circuits, which might be why your car thinks the temp is high. If your digital temp is ok, then your gauge is be just broken. Give that a try and see if it works. Good luck! Cheers, David. PS: I use deoxit from Amazon to clean and protect all my electrical connections, you just spray, and plug it in 10 or more times to clean. It leaves a film of what appears to be dielectric grease that protects and helps maintain an electrical connection. You might want to do this with your temp sensor. Even without the solvent, you can clean your temp sensor connection by inserting and removing the connection 10-20+ times. See if that helps, if it does, put some dielectric grease (or deoxit) on there and it should be good forever. That's the first thing I would try. Unfortunately, the seal at the sensor is weak, and you might spring a leak, but your o-ring is probably new so you should be ok.

[@amy40c]

@@DavidSunshine Thank you for your reply David. I already watched that video and it shows me this on digital display: "_ _ - 128" Should I try with the OBDII too or this is enough info? Hm good Idea, I will check all fuses but I think they are good because I tested the continuity/conductivity (with multimeter) between temp sensor connector and battery ground and multimeter gives a positive signal. I bought a new sensor so it cant be possible that it has dielectric on it. Also I checked al the wires that are going in the sensor and they are good and I get 5V on the connector.

[@DavidSunshine]

@@amy40c Hi, Seems like it's still not contacting the sensor. Seems like an open circuit. Did you try inserting and removing the plug to it about 20 times? If it's a connection issue at the plug, this will certainly fix it. A lot of times that's all it takes and it starts working again. That happens to the abs sensors, camshaft position sensors, temp sensor, coil pack, and transmission gear position sensor, in my experience alone. Cleaning the connector fixed all those issues lol. So give that a try. That's all I can think of is this case. If it's not that. Should try other things like the connections at the junction box. Cheers, David.

[@amy40c]

@@DavidSunshine Hi David, yeah I have short circuit somewhere but not close to the sensor. When I turn the ignition to ON position at that point my both pins on the connector are grounded (tested with multimeter continuity beep) and also between those two pins is short circuit. I checked wires close to sensor but they are okay condition and no short connections. Looks like it is something behind the dashboard or close to ECU? 🤔 Im not so sure because I dont know for sure how the wiring goes. But thank you for your help we are going in a good way I think 😀

[@maxliu1151]

nice music at the end. NICE VID!

[@DavidSunshine]

lol thanks man! Should have been there, dual compound loaded 10" infinity subs, off a 450W clarion amp. Nothing crazy but definitely enjoyable and better bass than stock. Glad you enjoyed the video! Cheers! David.

[@maxliu1151]

@@DavidSunshine so did you modify the sound system on your E46? do you have any vids about it?

[@DavidSunshine]

@@maxliu1151 Nope, I left the stock system in there. I don't have any videos, but it was all straight forward. Just Google videos of how to remove the E46 stereo and follow that, be careful not to break the trim, I pulled too hard and it cracked the plastic, so go slow and don't pull too hard on plastic parts. I just added the subwoofer to the trunk and spliced to the speakers in the rear for signal. I did it brute force, ripped the plastic backing to the speaker and connected to the wires for left and right signals, my subwoofer amp had a speaker level input (I think most do), so you can connect to speaker circuits like that and get the signal easily. Just connected to the positive terminal block beside the battery, and negative to the body. I did get a switched12V from behind the stereo and brought it back to turn on and off the amp with the stereo tho, that was a pain to do. I also added an aux 3.5mm kit to the stereo, you can buy those for $30, definitely worth it to get good quality sound from spotify or mp3s. Those are the two upgrades I would recommend, an amp and aux. You could just burn mp3s to a CD, that works pretty well and produces good quality, but CDs are a hassle to handle, so the aux cable is worth it. Cheers! David.

[@maxliu1151]

@@DavidSunshine Thx for your patient reply! it is useful and I will think about that since I am having a convertible E46.

[@DavidSunshine]

@@maxliu1151 Anytime! If I were to do it again, I'd probably install a compact sub unit, they have a lot out there. The convertible has less trunk space so something like a Pioneer TS-WX130DA would be nice. Look into it if you're interested in some more bass. Cheers! David.

[@supernova1976]

thanks for the great video. I have a different situation with my Turbo diesel Vw. on the cold winter days if I don't drive it over 110 on highways it never reaches temperature I can drive all day In city traffic ic and it stays cold even the heater is just warm not hot as soon as I stop on the lights it cools even more. any ideas?

[@DavidSunshine]

Hi, I have no experience with that problem, and I've never had a VW or worked on one, but first thing that comes to mind is air in the system, which would explain the cold during idle and hot while running. Maybe bleed the air out of the system and make sure it's topped up with fluid?

[@DavidSunshine]

And you're welcome! Glad you thought it was good! Thanks for the comment! Please let us know how it works out for you. I'm sure your findings will help others with the same problem too! Cheers. David.

[@Mw-so6he]

Hey buddy you never showed how to clean the thermostat?

[@leopold9999]

Interesting!

[@DavidSunshine]

Glad you think so, I thought so too, and that it was worth posting a video of. Hope others think so too! Cheers, David.

[@iLoveEatingPie]

Why did the termostat wax spill out when you heated it outside the casing? Is the thermostat itself not sealed and the heater directly contacts the wax?

[@DavidSunshine]

I let the heater shaft pop out, so the wax came out. If it's installed in the casing it's restricted and doesn't pop out, so you won't lose wax. The heater is directly in contact with the wax, so that it can melt it and act as a piston to open up the valve, it's sealed so the wax doesn't come out, but over time it probably wore out, and some wax got it, letting air in, and that's probably why it wouldn't close completely. After 12 years of operation that's expected, so probably needs to be replaced. Cheers! David.

[@AndyNav1]

Hello again, I installed a brand new thermostat. I checked it with heated coolant and it opened at the temperature a bit higher than that indicated on the thermostat (97 C, or 207 F); I checked with the vendor they said it's normal that it opens higher. Then I filled up the coolant and bled as best as possible. Now the heater is hot when driving and only warm when idling. I check the coolant temperature Live during driving, with a code reader, it never reaches that high temperature. The air temperature is around 0 C or 32 F. I check the lower hose it is always cool, meaning thermostat is closed even after one hour driving. My guess is that because of this there's still air in the system, so I get warm not hot air at idling and the lower hose remaining cold. I'm pretty sure the thermostat is ok. Please let me know what you think and how to remedy this. Temperature gauge acting normal staying at 12 o'clock after warm up. Thanks again.

[@DavidSunshine]

Hi, You're right, it does sound like you have air in there, keep driving it, and keep bleeding it for a while, and hopefully you get the air out. I think I had that happen to me too, warm until I got the revs up, then warmed up. The cooling system has this problem. Even in my x5m it gets bubbles up in the turbo cooling system, and takes a while of running to get the air out. Just drive it like normal, and floor it a few times on your drive, that'll help push the air around. Try the bleed procedure again too. It didn't work fully for me right away either, but if you keep at it, it'll get better. Cheers, David.

[@CombatVeteran13]

Just wondering but what is the part number for that specific thermostat housing?

[@DavidSunshine]

This is the one I used to replace mine: 11537509227 Cheers, David.

[@arnolduk123]

Great video, esp the thermostat operation part. How long should it take before the thermostat opens using a direct 12v connection as you did. Couldn't tell as the video was speeded up. I've connected mine to a 12v power source and it draws around 2Amps of current but the thermostat still remains closed after a minute. The thermostat is stuck in closed position and my engine is also overheating to the point of ruptering the top coolant hose. Is it bad thermostat ?

[@DavidSunshine]

Sorry for the late reply. You probably have this figured out, but ya, sounds like a bad thermostat. They should be replaced every 10 years in my opinion. It should only take about 10 mins to fully open. Not as quick as 1 min, but after 10 mins if it doesn't open like mine did, it's probably bad. I think my thermostat only pulled 12W or 1A @ 12V, not much to get it to open. Yours pulls 24W, so definitely should open pretty quickly. Hope you got it figured out. Cheers! David.

[@arnolduk123]

@@DavidSunshine thanks, I just replaced it to be safe. turned out to be a faulty viscous fan not cooling the engine enough. your video helped either way.

[@DavidSunshine]

@@arnolduk123 Glad it got it fixed. Thanks for the feedback too. That will certainly help someone else who has an overheating engine because of the broken viscous fan. Cheers! David.

[@Ash2theB]

I have a 2001 e46 and I have noticed my engine run cold. The mechanic said it's my fan needs to be replaced and my rpm are too high. I got a code that engine running lean probably because of P1619 my thermostat losing power.

[@DavidSunshine]

Ash2theB Hi. That doesn’t sound right to me. If the fan is broke it’ll overheat. If the thermostat doesn’t have power it won’t affect much, since the electric heating is only to force additional cooling when the computer knows you’re constantly pushing the engine hard. If your car is running cold when you’re driving on the highway, but warms up when you’re sitting in park or stop and go traffic, then it’s most likely a thermostat that’s stuck open, like the one in this video. Hope that helps! Cheers, David.

[@diegorubio8312]

I’ve replaced head gaskets, thermostat, expansion tank, radiator on 2000 323i and my coolant light still turns on when I turn my car on stays on for like 20 minutes then it turns off what’s the problem ...?

[@DavidSunshine]

Diego rubio Hi, Sounds to me like the new level guage is aftermarket. The stock bmw is particular, and doesn't indicate low level as easily. If the magnet is too close to the reed switch it'll inadvertently activate it even tho your level isn't low. The magnet may become weaker over time, so in a few months it'll stop doing that, but if you don't want to wait, you can cut 0.5cm off of the top of the level stick and it'll increase the gap between the magnet and sensor, that may keep your light from coming on. This is assuming you've bled the air out of your system properly, there's a bunch of videos on it. Good luck! David.

[@howlingmedia4354]

I have a 02 325i and I replaced the thermostat last June, and I hooked up the car soft obdii and it says 7b activation ,map cooling ,is it possible the thermostat went out that fast ?

[@DavidSunshine]

Hi, I wouldn't expect the new thermostat to break that quickly. It sounds like that code is saying the heater element that I test in this video isn't working right. Maybe just a bad electrical connection. I've had various issues with electrical connections in all my BMWs, causing cylinder misfires (loose coil pack connection), air bag error lights (loose airbag connections), reduced engine power (loose camshaft position sensor connection), engine temp (loose connection), and they were all fixed using a contact cleaner (Deoxit is preferred, but any works. If you use one without protection, you can add silicone spray or dieletric grease to the connector after to protect it). Without buying deoxit, you can try unplugging and replugging the connection 20-30 times(This worked for all my connection issues), and if the error goes away, it was that connection. If you don't add protection(deoxit it or silicone spray/dieletric grease) to it, it could go again in a few years, or never go again(I didn't protect my coil pack, and it worked for years). Unplugging and replugging just cleans off all the oxidation(rust) that's formed, which typically prevents the connection and throws codes/errors. Give that a try, it's free and has worked for me in the past. I've actually purchased a few cans of Deoxit and have gone through all my car connections of all my BMWs and cleaned them, it has worked very well for me, I think it keeps the system operating in a much more stable way. Here's a picture of the X5M Integrated BCM right before I disconnected and cleaned every connection, it's hundreds, and if you don't clean/protect them, any issue can pop up and give you trouble: www.dropbox.com/s/kxqhqhfqb3owfez/BMW%20X5M%202013%20Wiring%20at%20BCM%20IMG-20181205-WA0008.jpg?dl=0 Look up the procedure of using Deoxit, they basically spray and unplug/replug 20-30 times. I did an extra step and sprayed some more to wash out the gunk. It doesn't hurt to overspray and over clean. I spent 2 days on my X5M cleaning everything I could get to. Because I had two electrical issues pop up in the same week. The whole car was falling apart on me since it was sittiing for a long time, built up oxidation, then I drove it a lot; the combination of vibrations and oxidation lead to bad results. Hope that helps! Cheers, David.

[@jeffk5386]

When the thermostats bad, does it trigger a check engine, light or service engine?

[@DavidSunshine]

Hi, thank you for the great question! No not at all, it will overheat the engine until boil over, or over cool the engine and sludge up your engine oil leading to further damages. There's no safe guards on it except the temperature gauge that the driver needs to keep an eye on and fix if it's not stable at a proper operating temperature. It's crazy that the ECU keeps track of everything but doesn't warn you at all or even a check engine light or beep until something major fails. You'll need to trouble shoot on your own. They typically fall open, so in the highway your temperatures may go too low, that's an easy way to tell your thermostat is failed open and you need to replace it, cuz you don't want your engine running too cold for too long. Cheers! David.

[@PG.9]

About 3 C˙. 5km or 10 min driving is a lot of time for warming up? When my car waming up the coolan temp about 89-95 Celsius. Everything is alright? Thank you.

[@DavidSunshine]

SX320i Yup that sounds normal to me. There's a lot of water in the system so it takes a while to heat up. If you have heat on the highway it means your thermostat is working. If you haven't flushed and refilled the coolant you may want to do that though, may help with the temperature regulation, making sure it's a 50/50 mix. Sounds like there's some variation and it could mean you have 40% water, which is fine for cooler climates, but I recommend 50/50 for moderate climates, -10C to 35C. Cheers, David.

[@PG.9]

Thank you Master!! :)

[@williamfigueroa6662]

David, when you put 12 v to test, the thermostat, how long have to wait to get open ?

[@DavidSunshine]

William Figueroa About 5-10 min. or less. probably starts at 2-3 min. fully extending takes longer

[@iggydanko7998]

how did you connect the wires from the battery to the termo, you never showed the connect you made

[@Higgs000Boson]

You can connect it in any way you want. You can use, e.g., alligator clips.

[@robroberts2064]

What we're asking is - is there no need for a current limiting resistor? Just hook the thermostat heater directly to the battery?

[@giantmanpetrus194]

My BMW 320d overheats when you drive at high speed, what might be the problem?

[@eddiejenkins6876]

How long did it take for it to open with the 12v put to it?

[@DavidSunshine]

Probably about 1-2 minutes. Not much longer than that.

[@wakjob961]

My 2000 323I only gets to just past the blue on the dash gauge...48-54C. -17F the other morning...damn cold ride to work ;-(

[@DavidSunshine]

Lol same with mine when it was stuck open. Until you replace it, you can put cardboard in the front grill on the inside and just tie it in place, easy to do it you open the hood, since the grill goes up with the hood, you can just place the cardboard in there and tie it to the grill with some rope. I assume on the highway that you're going 100kmh and it's below freezing there. The cardboard will keep that cold air from rushing in, and if you do need cooling, the fan will kick in. As the weather gets warmer, just cut some openings into the cardboard to allow for a little more cooling. You just want to make sure it's getting up to operating temperature, making sure to not go over. Worked fine for me until I could get it replaced. This also works when it's -40C out, any engine, no matter if it's working properly, will need a front grill cover for highway driving. That's how they do it in Northern Canada. Cheers! David.

[@justinlopez8879]

Right where my thermostat is located on my bmw 528i it's steaming excessively but my temp gauge is normal, any ideas??

[@DavidSunshine]

The temp gauge is actually located very low, so if you have low coolant or air in the upper portion of your system, it'll read a normal temp, read a normal coolant level, but be overheating and creating steam, and boil over. You may want to bleed your system. Google how to bleed the cooling system, it's actually pretty strange for these BMWs cuz of the electric pump. Don't turn the bleed screw too hard, it breaks easily! And if it breaks, you need a whole new upper coolant hose assembly. Good luck, David.

[@samuelpiet6806]

My temp gauge stays center but water light came on and top pipe of radiator is hot and bottom cold ,can it be the thermostat, replaced water bottle recently, cos a leak....

[@DavidSunshine]

Hi, It sounds like the coolant level may be low, and there might be air in the system. Try performing the bleed procedure for the E46 coolant system. Careful with the bleed screw, I broke mine cuz I turned it too tight. I had the same problem after I replaced the expansion tank as well. The top hose might be full of air. I doubt the thermostat broke right after you replaced the expansion tank. Bleeding the air out is a pain, I could never get it right and instead would just run the engine and overfill the expansion tank, high rev it a few times(coolant will splash out), but that'll get the bubbles out, if you are impatient. Otherwise it can try the proper bleed procedure. Make sure you park the car on a level surface or slightly uphill (I think that might be better). Good luck! Cheers, David.

[@AndyNav1]

Hi Again, after 9 months! Would you please share how you made the plug connecting to the thermostat. I have to make one to force the thermostat open while the engine is running to properly bleed the coolant. Thanks a lot.

[@DavidSunshine]

Hi, I just used alligator clips to connect to it. There is no polarity, so you can connect 12v either way. If you want to permanently connect it. Just cut the connector wires and connect 12V to it. Cheers, David.

[@AndyNav1]

@@DavidSunshine great thanks

[@DavidSunshine]

@@AndyNav1 Anytime! Cheers, David..

[@howlingmedia4354]

I bought a thermostat from eBay and received it yesterday ,and I'm having to put up a big fight trying to connect the lower radiator hose to it .Have you ever had this type of trouble before?

[@DavidSunshine]

Hi, It could be that it's not manufactured exactly as the original. Is it a good brand? I found eBay parts to be there worst. I buy from local auto parts stores now. The parts from eBay always seem to cause troubles. Remove it and compare it to the original with a caliper, you may find something is off. If it's simply a lip that's too big, maybe you can file or sand something down to make it fit? I've heard of the same issue where the person has double o-rings, check to make sure that's not the case. Good luck! Cheers, David.

[@brendam455]

Gezz i am struggling to put that back and when you did it with needle nose i was like ugh 😑

[@BimmerDope]

hi david...i put 12v 2 amp power supply to my behr thermostat.it did not open after 16 mins...i had a leakage.can u pls mention the connections...which of the 2 terminals is +...help..pls

[@DavidSunshine]

Hi, It only pulled an amp so your power supply should have been good. I don't think there's a polarity, since it's just a resistive heater. It must not be functional? Take it out and see if the tip gets hot, be careful cuz it's really hot. If so. The wax may have leaked out and there's not enough in there for it to operate. Not sure if you can fix that. Might need a new unit. Cheers, David.

[@BimmerDope]

David Sunshine thanx..already ordered new one

[@adelemseek4806]

thanks for this v. how to test termostat aute car

[@DavidSunshine]

You're welcome!

[@bethells86]

Cooling system made complicated for very little gain, and high risk!! We have had one that does not open, which seems to the DME not wanting to send Open signal to it. Apparently the DME uses a few sensors around the engine to determine when this thermostat should open. Due to this setup M54 engines are prone to heating up and damaging, if one of those sensors are not working. Would like to replace this setup with normal thermostat, or have an independent temp. sensing electronics which controls this thermostat, and set threshold temperature to lower than 90 C.

[@DavidSunshine]

Hi, great point here! I thought that the thermostat functioned also with the wax temperature, and that it opened when the fluid got hot too(regardless of the electronic heater being on or off). The electronic opening is only used when they want to further reduce the coolant temperature, like when you're driving aggressively or up a hill; I've seen this demonstrated in a video before. That's a good idea, to add sensing electronics to control it. Since they just apply 12V+ to it, I would imagine it's easy to add other 12V+ inputs to the same heater using diodes, then you could run the thermostat with a bimetal thermal switch or a digital thermometer. You could put two methods in parallel for redundancy even. I'd use something like this, www.aliexpress.com/item/1pcs-12V-Top-Quality-LCD-Electronic-Digital-Thermometer-Moisture-resistant-Mini-Smart-Temperature-Controllers-Testers-Switch/32737786056.html?spm=a2g0s.9042311.0.0.27424c4dET0lRe You could put it in the car and see the temperature, and adjust when it turns on and off. You could silicone the temperature sensor and/or the bimetal switch to the aluminum part of the radiator. That's a little Mickey Mouse but should get the job done. I would set it at 95C so that it doesn't activate too much, and is only there when the cooling system fails, thus saving the engine from overheating; it's backup. I like to think BMW over engineered everything, but in all types of engineering, there's always room for improvement, and it's open minded people like you who think of it, and get things started. I had a similar problem with my Aux turbo coolant pump in my S63 engine, it fails, and throws no lights, so you could end up driving the vehicle for years without it operating properly. It will lead to turbo failure. They should have made it throw a latching hard code, but it doesn't. You can unplug the pump and it won't care at all. In that case, I was thinking the same thing, that I should install a redundant pump and have that turn on using a bimetal switch. There's not much room to add a redundant pump though, so I just replaced the stock one with a brand new one(that failed in 1 day), and I got a second one on warranty, that is still working, but I'm keeping an eye on it using a bluetooth energy meter, I check it weekly in case the pump fails again. These cars have issues, but we can manage. Cheers, David.

[@bethells86]

@@DavidSunshine Thanks for additional info. I was thinking of using a thermistor, some transistors and a relay. Might put something together when I have some spare time. FYI I we also have a later model X3 that only uses secondary electric pump, i.e. no thermostat. DME tracks engine temperature and emissions, and controls the water pump speed, of water back to the radiator. Once again, more complications and what if pump motor dies. However using a scanner I monitored three values while driving both X3s. Coolant temp into engine, coolant temp out, oil temp. Newer X3 (with electric pump) definitely runs a little cooler due as the the pump sending coolant to radiator earlier. The X3 with M54 engine runs to 96 degrees C before thermostat starts working, so runs hotter, which I am not comfortable with.

[@bethells86]

Bit pricey, but this is what we need: www.zionsvilleautosport.com/store/bmw-m54-competition-thermostat-housing-kit/

[@shefketmustafa9228]

1998 e39 528i Automatic, replaced the original BMW thermostat with MAHLE Thermostat it should open at 92C but it climbs to 102C is this normal? Thanks for the video?

[@DavidSunshine]

Hi, Ya that should be normal. It opens at 92C, so it should start cooling after that. 102C isn't too bad. It's a little hot, but it's a small engine so maybe they put a smaller cooler in there. You may have high antifreeze content in your coolant too, so the temp will generally go higher up than if you had more water. I'd run 50/50 unless you're in a really cold climate. Cheers! David.

[@shefketmustafa9228]

@@DavidSunshine Thanks! I noticed it opens at 94C and stays around 100C/105C while I'm driving. It worries me, after short drive (15min.) the lower hose (after thermostat) it has a lot of pressure built up when I squeeze feels like more air in it rather than the coolant , it's not hot like the upper hose (the one that goes to the expansion tank). Bad thermostat, water pump, blown head gasket, bad auxiliary water pump?? Engine only 30 000

[@TheEliteShatter]

Just wondering, by holding the thermostat how it would be installed, which is the positive/negative? Would like to perform the same test as well but unable to figure out which is which and can't see in your video.

[@DavidSunshine]

Hi, it's a resistive element so it has no polarity. You can connect right up to it with 12V DC or AC, it won't be damaged. Cheers! David.

[@TheEliteShatter]

@@DavidSunshine Awesome to know, would the condenser fan by chance be the same way? Always worried about trying to jump a part and accidentally shorting it out/causing more damage. Say I were to have it hooked up but the connectors accidentally touch would that cause damage??

[@DavidSunshine]

@@TheEliteShatter For fans, you'll want to hook it up with proper polarity, as they intended. Wiring diagrams will show which is + or -, and sometimes you can tell by the wire colors, brown or black should be negative, but might not be 100%. If you reverse a fan, it could just spin backwards, but you never know with these things. If they put a capacitor there, it could blow that, don't want that, so try to make sure you connect it in the right polarity. Cheers, David.

[@besofacacia6103]

yasterday, as became colder i found out mine is stuck open

[@olsigols3871]

My thermostat opens at 105 degree celsius E46 318i, N46 engine. Is there a way to make it open at 90 degree ? the car runs at 105 degree all the time by the manufacture

[@DavidSunshine]

Hi, I think you can buy reduced temperature thermostats. They come with various temperatures. The lower ones are great for longevity of the engine, but not great for fuel economy or emissions, as it's probably better performing with a warmer engine. Cheers! David.

[@justinlopez8879]

So would you recommend changing the thermostat??

[@DavidSunshine]

No, air in the system doesn't mean the thermostat has failed. But that could have led to boil over. If it's 10 years old, it's worth changing since the wax is old. You can try bleeding the system first, if it runs fine after that, you can choose to replace the thermostat as preventative maintenance, but don't really have to. It may have just boiled over because you have old coolant in there too, maybe too much water? You may want to replace the coolant if that's the case. You should check the easy and cheaper things first, before replacing it. Cheers, David.

[@cichandler833]

So like if my car is like at <a href="#" class="seekto" data-time="730">12:10</a> to <a href="#" class="seekto" data-time="750">12:30</a> it most likely is stuck and caused it to overheat?

[@DavidSunshine]

I would check the temperature, if it's above 95C then that's kinda hot, but if you got a high temp thermostat it might go higher. You can check the temperature in the console, you don't need to buy anything, just need to push a bunch of buttons. Look up procedures on how to check temperature on E46 cluster and you'll find it. If it's overheating in the red, don't drive it, you don't want to overheat your engine. Cheers! David.

[@wzrdkelly1054]

Hey so I disassembled my thermostat and i see no wax where you instructed it should be. Is there any fix or is it completely trash?

[@DavidSunshine]

Ya I would replace the whole unit. No point trying to fix it, they don't sell the wax. Cheers, David.

[@wzrdkelly1054]

@@DavidSunshine im kind of in a bind right now, any quick solutions until i can replace it?

[@DavidSunshine]

@@wzrdkelly1054 Ya if you can't get a new one, you can just bend the valve so it stays open about 50%, leave the 12V disconnected. You should be able to drive like this for a few days of it's moderate temps out. If it's really hot then maybe leave it open about 80%. You'll run a little cool if on highways at night but it should be ok for a week, after that you'll have side effects of running too cool, so replace it as soon as you can before you cause any long term damage from running too cool or hot. The cooling capacity of the radiator is huge tho, so you'll most likely run too cool than too hot unless it's hot out. Just keep an eye on the temp and let it cool if it's starting to get too hot. I ran with mine open all winter and it just ran cold on the highway, I didn't notice any moisture in the engine oil but changed it out soon as I replaced the thermostat because I'm sure I would have started getting corrosion internally if I left it too long. You can leave it really open and use cardboard on the front to keep it running warmer on highways, that's what I had to do on the winter before I could replace it with a new one. But replace it soon so you don't run the engine out of normal temps. Cheers! David.

[@tainiak2008]

I got bmw 330ci and my fan clutch its very loud i change the fan but is stil the same its very loud and never gets off

[@DavidSunshine]

That's strange. Did you try turning the engine on without the fan in place, to see if the sound is from something else? The fan clutch doesn't seem like it would make much noise. It is supposed to spin all the time, that's not a problem actually. There are electric fans that turn on in addition to the fan with the clutch. What noise is it making?

[@tajmeeltarfeeh7030]

I Have replaced the fan clutch, still the temperature is going up, on slow rpm, while it go back to 95 , when moving fast or on high rpm accelerate, do you have an idea what could be the reason Thanks for the video

[@anayansilopez868]

Hi guys I have a problem with my E46 M3 2003 I did change the whole cooling system and the car still overheating on traffic or going up to hills I did replaced the thermostat two times the fan clutch too and still have the problem. Please if any body know what's the problem please let me know thanks

[@DavidSunshine]

Hi, If you have all new cooling components, it could be air in your system that causes overheating. Even a small amount of air in your system will cause overheating. So apparently the proper BMW method of bleeding the system, is to park it on level ground, and then turn the ignition to position 1(DO NOT TURN THE CAR ON), and have the interior fan blowing at the lowest setting(to keep the battery from dying), and then turn your heat/temperature on to MAX setting (32C for me, or ##F for others), this gets the electric pump to the cabin heater core pumping, and valve open, now you remove your bleeder screw, remove the coolant reservoir filler cap, and then slowly poor in fluid until the fluid comes out of your bleeder hole(removed the screw completely). You'll see that bubbles come out, that's good, you're expelling air from your system. Then you let it sit for a bit, and add more fluid, I would do this and let it sit for about 10 minutes, waiting and slowly pouring. After flushing about 500ml through it, and only having fluid come out, then all your air should be expelled from the system. You can siphon out the excess fluid from your reservoir until it's down to the level of your float(you don't want to overfill the system), close it all up, and you should be ready to go! You can heat it run, run it to hot, and do this again until even more air is out of your system, but I haven't found this to be required. Anyways, hope that works! Cheers, David.

[@alexvids9232]

now i know mine is not stuck open. thanks

[@dolphinsfan137]

I have a 00 328ci my engine is over heating... and leaking coolant.. the reason this all started is the fan wasn’t plugged in the sensor got unplugged and it over heated and exploded on the side of the road... coolant was everywhere. Since then I bought a new expansion tank and expansion tank mount because the old one broke comming off.. i am still leaking. I can’t find the right o rings at auto zone or anywhere. They don’t have them! My car is still overheating and leaking.. I think it may need a thermostat or water pump because it’s still overheating and when I tried to bleed the system I noticed there was no heat. I’m 18 years old and can’t really afford to have it fixed at a shop and i am more of a do it myself kind of guy. Anybody know anything that could help? Also I had to take the transmission cooler off to install it and now it’s throwing the transmission light at me...

[@fat_dorito2332]

So I have a 1997 E36 328i and it only overheats when I just stand on a red light but when I get on the freeway and go about 50-60 mph it goes back to 12 o'clock. I've been searching this problem for 4 hours now and everyone has a different problem.. I just want to be sure about what I'm about to buy. I flushed the radiator out so far now I don't know if I should buy the fan clutch? Or the a/c fan because my A/C fan doesn't seems to be working or spinning when the car is overheating. So I think it's three choices here and I don't make a lot money. Fan clutch, a/c fan- aux fun, or thermostat. Help, leo

[@DavidSunshine]

Hey Leo, I understand that you don't want to spend a lot of money when fixing a problem in a car, and most people don't have unlimited cash either, so it's not a good idea, and is just a waste of time and money. You should troubleshoot the problem to find the actual source of the issue, rather than replacing parts, hoping they will work. With your issue, it can be a number of things failing, but I would first check the fuse to your aux fan, sounds like that's the issue, I would get it running first. If the fuse keeps blowing, spin the fan to see if it spins freely, it might be sticking, maybe you can take it out and just spray it with penetrant/lubricant, like WD40, to get it clean and going again. Might want to spray brake cleaner in it to get rid of any gumming grease. If your auxillary fan isn't spinning when the car heats up, it sounds like the only issue for you is the fan, since with good airflow going 50-60mph your car runs fine at 12 o'clock. Your temp sensor may have failed, like Colin's E36's, he wired a switch to the high mode, so he can turn on the high mode all the time, this might help your issue, and it's free. It would be even easier to just cut away the insulation of the wires, and short them together, tape it together, and get your fan spinning. If that fixes your issue, you know for certain it was just the temp switch. Check out his video here: kzbin.info/www/bejne/sJ6bZZaGg7Caf8U This user also test the fan with a jumper, you could just leave that jumper in there, assuming it stays off if the ignition is off: kzbin.info/www/bejne/bIrUYYeffsSVi80 I don't think the fan clutch is going, since you're overheating at idle, it doesn't spin very fast at idle. I think it spins faster when you rev the engine, but that would cause overheating when you're using a lot of accelerator, which isn't your issue. Your issue is overheating at idle. I assume you live in a very hot climate, so you need your aux fan going, I'd just run it 100% of the time, and not bother with a switch. So troubleshoot things before you spend any money. Cheers! David.

[@tadashykiro3759]

I have exactly the same problem, can you tell me how you fixed it?

[@floriangjikondi8603]

I am having the same problem. mine is a 320 diesel e46. it has a hard time to warm up,and on the highway the temperature drops almost all the way down. also when I turn on the heater it drops. I replaced the thermostat,the old one came out in pieces,but I am having the exact same problem even with the new FEBI thermostat. could it be the thermostat again? I scaned the car and it dit not show any code for the thermostat like P0168. any ideas please?

[@DavidSunshine]

Mine didn't show a thermostat code, but it was definitely stuck open, cuz it would warm up sitting in traffic, but as soon as there's airflow or would cool down since fluid was going through the radiator. Does that sound like your problem? If so, the fluid is probably travelling through your radiator, which means you should replace the thermostat. Maybe the new one got some pieces stuck in it and bent it or made it stay open? That's all I can think of. Also, first thing I would check is to unplug the 12VDC connector, you don't need it anyways, you'll just lose the ability to open it early in cases where you're racing around a track. My thinking is, the 12V relay might be stuck on for some reason. This will help test that out. If no change, then you can plug back in, it won't hurt or help much either way. If the problem still persists, I would replace the thermostat, and flush it really good when you have the thermostat out, to get any debris out of your system, after that it should work like a charm. I'm the highway I got no heat, even with a slightly open thermostat, doesn't take much, so a piece of something would have bent or caused it to stay open. Hope that helps! Cheers, David.

[@floriangjikondi8603]

David Sunshine yeah you're right I should check that again,maybe the relay is faulty I don't know but I should check it. on the highway it drops from 85 degrees to 57 for about 7 km. also when I turn up the heat it also drops. thanks David for the info and the video,really helpful and Happy New Year

[@DavidSunshine]

The chances that the 12V is being applied is very low, I would think, but you never know, so worth testing it out before taking it all apart and replacing the thermostat. When you replace the thermostat, I would flush the system with a hose if you can do that too, if you do have plastic bits in there, you'll want it all removed before you put another thermostat in there. You can buy adapters to connect hoses to the radiator houses, to push water through the system, it's a good way to flush and clean it out. Then you can drain it using the plug under cylinder 2. If you don't want to flush it, just draining it with the plug under cylinder 2 gets out quite a bit of fluid, you can always open the plug, and poor water down from the top, that might wash out some plastic parts as well. To me, it really sounds like fluid is flowing past your thermostat, once you have that sealed up, it should be able to warm up right away. As soon as I replaced mine, it warmed up no problem on the highway going 100km/hr. Before that, it would cool down within a few kms. Turning on the cabin heat shouldn't reduce the temperature that much though. Before replacing the thermostat, I think you should test that 12V plug, and also bleed your system and make sure it's got no air bubbles in it. But air bubbles typically cause overheating, not the over-cooling like you've described, but best to make sure you've bled the air out anyways. Hope I could help! You're welcome. Thank you and have a Happy New Year too! Cheers, David.

[@floriangjikondi8603]

David Sunshine yeah you've been a great help,I am going to test the 12V plug as soon as I can. thank you again and take care.

[@3ManFunny]

so today i removed the termostat applied 12v and it got hot and opened after that closed and the car is giving me map cooling error should i change it?

[@DavidSunshine]

Hi, it might just be a code left over from when it was unplugged. Or the connection is loose. I would try unplugging and plugging it in 20 times with contact cleaner and then checking again. It's always possible it's a bad contact, rather than a bad heating element. If the heating element is actually dead, then I would get a new thermostat, but I doubt that since you tested it and it worked fine. Cheers, David.

[@3ManFunny]

@@DavidSunshine So today i replaced the Thermostat with brand new Behr one and the error is gone after i clean it up and not reappearing so i guess it was something wrong with the last t-stat (it was 7 yr old)

[@FPSAnarchy]

I bought one at scrapyard, is 15 seconds good for the electric heater to open the thermostat?

[@DavidSunshine]

Nice! Ya that doesn't sound so bad. As long as it can fully open and close properly, you should be good. Mine had a bent shaft, so it was jamming open, causing a cool engine that couldn't get up to operating temperature. Cheers! David.

[@FPSAnarchy]

@@DavidSunshine I wish mine failed open, the problem with mine right now it sometimes fails to open in time, and opens around 125c.. i hope this will fix

[@DavidSunshine]

@@FPSAnarchy Ya it'll probably fix it. That old one sounds like the wax is getting old and might have leaked out a bit. If the new one you got has only been used a couple years it should be good. I think they are good for about 10 years, then they start to wear out. Good luck! Let us know how it goes! Cheers! David.

[@PitBull2424247]

Have an E46 that overheats thermostat, radiator, hoses and water pump have been replaced and it still overheats

[@DavidSunshine]

Hi, If you can confirm that the water is pumping and the system is bled of air, and everything is new and working properly, the electric fan or the clutch for the main fan might not be working properly. I would check those next. You can read the coolant temperature from the dash, there's instructions for it in the description of my video, and you can search "E46 coolant temperature readout" on KZbin and you'll find videos on how to access it. Cheers, David.

[@loosegooseconceptsatl6690]

ima try tomorrow ... lets what happens!!

[@DavidSunshine]

Good lucky!! It's pretty easy, one of the easier jobs on the E46, as long as you can get that fan off with a big wrench. I hammered on it in the clockwise direction to get it off, if you don't have the tool to hold it in place, you'll want to do that. I describe it in the description. Cheers! David.

[@Yophillips3272]

What happens if the electric heating element is broken? Will it run hotter? Mine is broken but it doesn't go past the middle. But it definitely goes over 100C, 110C max if I check the temp. 🤔 Stock stat says 97C

[@DavidSunshine]

Ya you got it, it'll run hotter for sure. It sounds like the wax in the thermostat is still working fine, so it just operates like a traditional thermostat, but it'll run a little hotter since the ECU isn't capable of forcing it open at 100C, thus going over to 110C. It's not great to be running that hot, since you risk boil over when you go up a big hill; that's when the ECU would force it to open further, since it notices you're giving it extra throttle and it'll work harder. I would get the thermostat replaced, it's a fairly cheap part and will keep your engine operating in the normal operating temperature range. If you don't replace it, you've gotta be careful on a hot summer day going up a steep hill, or any other situations where the slow reacting thermostat would cause overheating.

[@Yophillips3272]

@@DavidSunshine I replaced the thermostat it does seem to be running a little cooler but not much of a change. Maybe since it's not really overheating I shouldn't worry about it so much. 🙈

[@DavidSunshine]

@@Yophillips3272 Nice! Ya the engine needs to get up to operating temperature and keep it there. If it's holding steady around 100C I wouldn't worry. The needle should stay around noon. Keep an eye on that. If it goes way to the right then you can start to worry. Cheers! David.

[@noelsjostrom7335]

Which temperature in celcius should the thermostat open (e46 320) ? mine is not reaching the 12o'clock temp.

[@DavidSunshine]

It should open at about 88C. Seems like my new one is. If your coolant won't heat in up, your thermostat is probably stuck open. I would replace it if it's older than 8 years, it's most likely the culprit. Replacing mine solved my problem with it not heating up, unless I was in stop and go traffic. Cheers, David.

[@noelsjostrom7335]

@@DavidSunshine got my thermostat changed now. But stock e46 320 M52TUB20's thermostat should open at 97C so got myself one of those and now its working properly! Thanks!

[@DavidSunshine]

@@noelsjostrom7335 Nice! Ya, usually there's a few options in temp, lower temps are good for hotter climates, if you're in a moderate climate a higher temp can be used. Glad it is working well for you! Cheers, David.

[@mariomunoz4127]

hey I have a 2004 BMW 330i my car heats up and it blowed up my radiator any ideas with wats wrong with it?

[@DavidSunshine]

Hey, are the fans working properly? If it did that while driving at 50km/hr+, then it's probably the water pump not working, or the thermostat is stuck closed, or your fluid level was too low. Regardless, when you replace your radiator, you're best off replacing your thermostat if it's over 6 years old, they should be replaced after 6 years anyways(in my opinion, their life span is about 9 years max). Then properly fill and bleed your system, and make sure it's flowing and working properly, if you rev it up while the fill cap is open, it should flow enough to splash everywhere, if that's not happening, your water pump might be damaged and not pumping properly. Make sure the auxillary fan and fan clutch work properly, if you have good airflow at idle and it doesn't overheat, you're set. Those are the things I would check. Cheers! David.

[@snowhiterover]

Mario Munoz check for CO2 in your coolant, if that is fine. then your thermostat is probably stuck closed. this happens to me, blew the radiator.

[@dziabi3]

super

[@DavidSunshine]

Thanks!

[@jorgelopez1413]

hey whats up ,what happens if i leave the car without thermostat should menton i live in a quite template climate

[@DavidSunshine]

Hi Jorge, if you live in a temperate climate, you might get away without having the valve in there, but your engine will run cooler than it should, and moisture/acid will build up in your engine, causing corrosion and degrading of your engine oil, it's overall bad for the internal workings of the engine. You might see deposit build up, and that's a sign your engine isn't getting up to operating temperature and boiling everything off that it should. Bad things could happen if you run without a thermostat that helps keep the cooling at around 90 degrees Celsius. I would recommend putting in a working thermostat. Hope that helps! Cheers, David.

[@jorgelopez1413]

David Sunshine thanks david its true better change it

[@DavidSunshine]

You're welcome. Ya I think it's pretty important for that thing to operate properly, it'll keep your car running in the best shape.

[@brendam455]

By the way my temp gauge has been stuck to all the way on high rest it on cluster and it moves but goes back to hot car not even on also used another instrument clusters and still does the same. Temp sensor new the whole cooling system new.

[@DavidSunshine]

Hi, You can first check the read out using the cluster (kzbin.info/www/bejne/bnbHYpucZdWJfc0, item 7) or a generic obdii read out and the torque app. Have you tried checking the codes using an obdii checker like Carly? It'll tell you the codes from the modules, the generic readers won't give you all of them. Cheers, David.

[@brendam455]

@@DavidSunshine yeah I do 7 gauge cluster every time I get in because I can't see the temp so I do it through the cluster. And no codes on 5 different scanners

[@DavidSunshine]

@@brendam455 Oh ok so the sensor is fine, just the cluster isn't showing. How about when you use 2 to test the cluster? Does the needle go the full range? If not then it'll give you some ideas to start troubleshooting. Cheers, David.

[@brendam455]

@@DavidSunshine yes it test fine and resets and then after turning car off back to high temp

[@tengzturiagaiii3185]

Since you showed how to take it apart and cleanning it. Is that really possible? I think my thermostat is stuck open. When i idle specially in cold weather my needle goes up to the second line. At 11 oclock. When i start driving at 35 to 45 mph it goes lower. Then when i’m stopped at the light it goes back up to 11 oclock.

[@DavidSunshine]

If you want to try and save some money, you can take it apart and clean it and bend the shaft back straight, it'll function properly if you can fix the issues. But it's probably better to just replace it with a new one. Mine got old and failed open as well, it got cold just like yours at speed. I put cardboard in the grill to keep it warm in the winter until I had time to replace it. You can do that too if you need to drive and want the engine to warm up. With the cardboard in the grill, it still works fine since the fan will come on when it's too warm, the system has a lot of cooling capacity so the chances of overheating are very low, but keep an eye on it if you're stuck in traffic. It's typical to put covers on grills in the winter if it's cold enough. Cheers! David.

[@tengzturiagaiii3185]

I have discovered another issue this winter. My lower hose collapesed after driving and parked. When the engine cooled down. I check it and noticed my lower hose had collapesed. I searched about it, a lot are saying reason for collapseed hoses at vaccum in the syatem. And adviced to replced my resrvoir cap. How does the cap works on bimmers since it doean’t have a spring in the cap like most vehicles? cap? Btw, you mentioned wax is used to heat the cylinder in yhat electric heater for the spring to pop out? Is the re a fuse for the two wire plugged in the thermostat? If so do you know which nunbet in the fuse box? Thanks Tengz

[@DavidSunshine]

@@tengzturiagaiii3185 The cap should let air in if there's a vacuum but hold pressure in. It doesn't have a spring but there should still be a spring and check valve internally, that may be stuck. I've never taken one apart but I suspect it is the same as other caps in function. They are probably right that a replacement would solve that issue. Cheers! David.

[@tengzturiagaiii3185]

Cheers. Thanks David. I’ll give it a try replacing the cap first. Before i try taking the thermostat apart. Thanks Tengz

[@LilMell24]

Please tell me OEM code of this shaft/sensor.

[@DavidSunshine]

Hi, It's best to replace the whole housing, 11537509227 is what I used. I'm not sure if you can buy the sensor separately. I couldn't find it, probably cuz they want to sell more parts, but more importantly it's good to replace it all as an assembly. Cheers, David.

[@themisterwithnoname]

I have an e39 523i and my thermostat is stuck closed. Can i simply remove the thermostat?

[@DavidSunshine]

Hi, the car won't run without it. You'll need the housing in there, you could remove the valve, and run the engine cooling at all times, but this is bad as the engine will run cool and damage will occur over time. I would suggest replacing the thermostat since it costs $120, but will save you thousands in damage down the road. Cheers! David.

[@themisterwithnoname]

@@DavidSunshine yeah im going to replace it but tomorrow i need the car thats why i need to run it cold. I live in Portugal so we dont have that much cold here. Thanks for your reply

[@netw0rkzer0]

hello, I have a 323ci M52 E46... but my temp is hitting the 105 - 106C... not sure if is the FAN or the thermosthat, I already installed a Mishimoto radiator, for some reason the mishimoto thermosthat don;t fit the OEM housing, any ideas? It is normal for the E46 runing 100C or 105C temp?

[@DavidSunshine]

Hi, no it's not normal to run at 100+℃, must be something wrong there, or the thermostat you have in there is a high temp activated type, 205℉ or 96℃, that would explain it, if it's working fine and just running hot cuz of the thermostat, you're fine. The electric fan is coming on right? If you have a regular thermostat it should be cooler than that, unless it's hot out, then it might be ok. Not sure why it won't fit, might be for a different engine size? If your engine runs fine and it's hot out, it might not be a big deal as long as you aren't boiling over. If the activation temp is 96, I can see it hitting 105 then cooling and stabilizing between 100-105. Cheers, David.

[@netw0rkzer0]

thanks your your reply.. .Then FAN is working, but not sure if the OEM fans have 2 velocities, or just one? I;m going to try a new housing with thermosthat and try to fit the mishimoto one ... I;m from costa rica, and the weather temp over here it's a little bit high... about 18C-28C weather temp in the morning-afternoons . Sound fair that possibly i have a high temp activation thermosthat. But to be honest it's quite frustrating checking the temp goes to 106C :(

[@DavidSunshine]

Anytime. Mine was. At 90 but it was cold out, like 10C, I could see it being 106C at 28C out. Also what mixture do you have? Less water, and you'll have higher temps. I'd go 50/50, some do 60/40, haven't tested it but 50/50 should be safe. I'll check mine tomorrow. Your housing has the thermostat built in doesn't it? There are youtubers who replace the fan connectors with switches, from that video I think it was only on off, but I could be wrong. You should check his video to see if there are different modes.

[@netw0rkzer0]

yeap... thanks again... i'll try to find a used original housing and thermostat and try to fit the mishimoto one. I'm using coolant for the radiator 70 coolant 30 watter, the car runs fine, no leaks, no damage in the headgasket yet heheheh... but i'll try a used original one if everything goes smooth, i'll buy a brand new OEM housing and thermostat to replace everything. another problem that I have, is that i'm have the M3 cluster, and the iddle is not in 12 oclock, never is there hehehe... always is 3/4 of the cluster, or hitting the red color when they moved to 106C :(

[@DavidSunshine]

You're welcome. Hmm, if you're running 70/30 antifreeze/water, that might be why it's running so hot. The antifreeze doesn't cool as well, and has a lower thermal capacity than water. If you want better cooling, you could put more water, like 40/60 antifreeze/water, and see if that helps. 70/30 doesn't cool the engine as well, but it's great for freezing cold environments where it's -40C out. This page explains it a little better: www.reference.com/vehicles/much-antifreeze-should-mixed-water-a7f2ca45b34f9054 Water is one of the best coolers, that's why we're still using it over anything else. I would try 50/50. This page also explains it too: hellafunctional.com/?p=629 It also says cars run at 90-105C, so your car might just be running at the top of that range because it's not cooling as well due to the 70/30 mix. Before trying any hardware changes, I would adjust it to 50/50 and see how it works. If you have 8.5L of 70/30, you can drain 2.43L, then add back 2.43L of deionized water, it should be 50/50 after that. That should drop your temperatures some, maybe not down to 90C, but at least below 100C I'd think. Are you checking the temperature with the OBDII sensor and Torque?

[@gentlemen1020]

I have a 2003 330i that recently had the temperature gauge sky rocket to red within 5 minutes of leaving the house. This has never happened. I’m suspecting a thermostat that’s stuck close . Any comments are welcome .

[@DavidSunshine]

That sounds like you may have low coolant, check for leaks, and when cool, check the level. The expansion tank typically cracks, and has a super slow leak, once it's low enough, it can exhibit that temperature spike like you've been noticing. A water pump failure could also cause the same thing, if it's not moving the coolant, it can overheat in 5 minutes too. A stuck thermostat can also do the same thing. I would replace it if it's over 8 years old for sure. Mine only lasted 10 years. Good luck! Cheers! David.

[@texast1311]

What happened if the sensor is not workin by any chance? I replace a new thermo but is still overheat? Any ideas why?

[@DavidSunshine]

SKINHEAD DOG Hi, does your temp sensor read correctly? It doesn't matter if the heating element doesn't function tho, it'll open based on the water temperature. There are a few things that can fail, typically the fan, water pump, or thermostat. You already replaced the thermostat so check the fan. Is it overheating cuz the fan isn't working? Another common thing that causes overheating is a partially filled system, make sure you fill the system and bleed out the air properly, I do that by running the engine and revving it to push the air bubbles out while the cap and bleed valves are open, it'll splash a bit. Then after a drive, let it cool right down overnight and then bleed and top up again. If your fan isn't running, you can actually force it on, some other KZbinrs show how to do that. Hope that helps! Cheers, David.

[@texast1311]

David Sunshine yeahh the fan doesn't works. New water pump too. So the fan that causes is that right? Any ideas why there too much pressure in the hose and the coolant waters pourin out when left the lid open. And the lower hose hardly coolant water when engine is off?m. Thanks

[@DavidSunshine]

SKINHEAD Hi. Ya if the fan isn't working, that'll cause an overheat situation. If you're driving on the highway and there's sufficient airflow, it shouldn't overheat even if the fan is broken, have you tried that out? I'm not too sure about the water flow issues, but you should get the fan fixed first, that might fix the overheating issue. The temp sensor the fan might be the culprit, I haven't dealt with that yet, but I've seen some KZbin videos showing its replacement or bypassing. I'll try to find it here.

[@DavidSunshine]

SKINHEAD check this out, might help you troubleshoot kzbin.info/www/bejne/bIrUYYeffsSVi80

[@texast1311]

My fan works I've found the wires won't turns the fan on.

[@kkankava]

Hello Guys, First of all, Thank you so much for that video. But I have the problem with my e 46 cooling system (thermostat) also (I have changed 4 of them but the problem is still there ): Once I drive on the highway and the radiator airflow is Ok the temperature of the Coolant goes down up to 60. In the winter period, it is very difficult to heat up the motor also (it takes a long time). But when I off the connection wire on the thermostat the temperature range is Ok. The Error is P1619 - OBD2 (Cooling Control Circuit Signal Low; Map Cooling Thermostat Control Circuit Signal Low) Could you be so kind just explain to me what can be the reason? Thank you in advance...

[@joninumminen9205]

I got this same problem right now on my e39 😅 have u found an solution?

[@kkankava]

@@joninumminen9205 Unfortunately, not yet...

[@kkankava]

@@joninumminen9205 just one question: Did you change coolant? or did you add some special ingredients to the coolant?

[@kkankava]

@@joninumminen9205 After what it has started?

[@joninumminen9205]

@@kkankava have done nothing so far 😅 trying to solve what is the one cable that isint connected to anything, between intake and firewall? The connector has green rubber inside and 2 pins

[@Aacckkoo90]

My BMW e46 N42 318i have 100-105 temperature 105kw

[@7igerpr1nce]

Brother my e46 heats up and spews coolant on the ground but no leaks.

[@DavidSunshine]

Sounds like the thermostat is failed shut. Or it's low on coolant and wasn't pumping, that'll make it overheat and boil over. You need to fill it properly and bleed the air out. But if it was running fine and started boiling over, most likely you got a failed close thermostat, jammed in the close position. You can troubleshoot your system, or just replace the thermostat. But I would fill it with distilled water and bleed, and check the functionality of the thermostat and waterpump. That way you know if you have to replace the water pump and/or thermostat. Water is cheap, so it's worth it. I wouldn't do it with coolant, cuz you'll dump it to replace the thermostat anyways, or pump. My bet is the thermostat tho. Water pump might go if your car is high miles and you haven't changed out the coolant often. I've never had a coolant pump go on me tho. Cheers, David.

[@7igerpr1nce]

@@DavidSunshine brother my goodness thank you so so much..for replying. Your the man brother. You couldve totally ignored me. Its 2001 e46 bmw. Ill do exactly what u said. It dumps right under the engine bay on the side of the radiator. Thanks pal u helped a bunch. Ill start 1st thing in the morn tom.

[@7igerpr1nce]

One more thing pal.should i bleed it first? Or should i look at the t stat first? I have a vid saved on e46 bleeding so that shouldnt be hard. Ill even jack up the radiator side just for giggles.

[@DavidSunshine]

@@7igerpr1nce No worries. If it's 2001, the plastic is all brittle, so maybe you have some cracked plastic, but you said it wasn't leaking? Cracked plastic usually results in a spray at higher temps. It just overheats and then boils over? Make sure the belt is ok and is spinning the water pump fully, if it wasn't, you'll hear squealing and the battery light would come on too. Sounds like it's not pumping coolant, leading to overheating and boil over. But fill it up and check everything one by one. With the radiator cap off, you should be able to see fluid flowing, that means the pump is working. My belt once broke and it would overheat in about 7 minutes. The temp sensor still read correctly, so at least you can check that. Load up the temp reading on the cluster, you can keep an eye on the temp, if it goes to 103C I would shut it down, don't want it overheating too much. If you are gonna heat it up, you'll want some antifreeze in there, not all water, otherwise it'll boil the fluid, 30/70 - antifreeze/water should be ok for testing, ballpark is ok. For the temperature read out, check my description. There are also other KZbin videos that show how to access it on an E46. Cheers! David.

[@DavidSunshine]

@@7igerpr1nce I would bleed it first actually. This ensures you have it properly filled up. I'm not really sure why it overheated though. If you had old coolant and it was mostly water, and you overheated it car on a hill, you could boil the coolant and cause these issues. Was the coolant a proper 50/50 solution? I would start with a working system. And try to troubleshoot each component. If you bleed it and fill it, you can be certain that the pump will pump fluid correctly, if not, you know you have a failed pump. If the pump works, you can check the top driver side radiator hose, if it stays cool even though your engine temp is high, for sure you know the thermostat is stuck closed, and it needs to be replaced. Now if both are working, and you still get overheating, maybe the fan is not working? I forget, but you may have a clutch fan and an electric fan. You'll want to check that both of those are working ok. Did you overheat in stop and go traffic? If so, those fans may be failing. Fuse maybe. The control circuit for the fan sometimes goes. There are videos out there that show how to check the fan operation for the E46 too, may be worth a check. Those are things I would check first. Good luck! Cheers, David.

[@samobalco5744]

well better for it to stay open than not open at all