How to Bleed A BMW Coolant System

This video is a description of how to bleed a BMW Coolant System, this is an E36 model, but is applicable to most other models.
The main thing about bleeding the coolant system is you want to get the front end up in the air so that the system can bleed properly. You also should be running the heat at full blast.
The car will have to sit for several minutes to reach optimal temperature, at which point the thermostat will open up and allow the coolant to circulate. A way to tell when the coolant is circulating is to put a hand on the two coolant hoses running out of the thermostat, if both of them are hot, you know that the thermostat has opened up.
At this point the air bubbles should begin coming out of the bleed screw area, this will continue for several minutes. Once the air bubbles stop coming up for at least a minute, go ahead and put the bleed screw back on, turn off the car, and your done!
*This description contains affiliate links. If you buy a product through my custom link, I will earn a small commission at no extra cost to you.*

[@govivo2010]

Thanks for the video. Have done a few of these on E36 and not a lot of fun . Finally sprung for Mishimoto tank after second plastic tank cracked after 3 years both times. Added a Pegasus racing 3/4 inch OD aluminum splice in the overflow tank return hose under the airbox so can remove shroud and overflow tank as one unit after radiator. Also drill a 1/8 inch weep hole in thermostat to allow a faster air bleed ( hole rotated to top of thermostat ). Use upper radiator hose as funnel to fill radiator then switch ends to fill block and remaining hoses. The bleed hole and fill procedure reduces air bleed time a lot and top up in overflow tank to about 8 ounces. Takes one gallon to fill radiator and 3 quarts to fill everything else when block was not drained. Removed belts to avoid coolant contamination and sealed ends of hoses with 3M trim adhesive to block water /chemical ingress. The vacuum hoses under the L shaped air boot and the air boot crack causing idle surge . BMW boot lasts longer than aftermarket and can reseal cracked hose ends after rubbing alcohol cleaning with red silicone if not replacing them. Bel-Metric sell 6 mm nuts with rotating flange washer that deforms a little to soft lock the nuts. Hard to believe BMW spec of 5 nm on the water pump nuts but they are right on. Thanks again for very helpful video.

[@GNflyby]

Worked for me, thank you I can finally drive my car without it overheating!!!

[@e36fanatics29]

Thanks a lot glad it helped!

[@sniper2349]

I took that little screw out a few times when working on my coolant system. I had no idea it was the bleeder screw thank you!

[@anthonylangley1549]

Sounds like kip from Napoleon Dynamite... thanks for the upload.

[@djayk9692]

Chilton and BMW tech manuals indicate to fill the coolant system with the ignition in the ON position (electricity running only) with the heater on. Then actually START the engine after the level in the expansion tank no longer naturally drops. With the ENGINE now running, rev it with 3 short bursts of 4500-5000 rpms. This allows the water pumps rid the air of the system itself. After 30 seconds to avoid the engine from heating up and coolant expanding, tighten the bleeder screw and shut the engine OFF. Check the expansion tank coolant level and fill to the appropriate level, replacing the cap. Restart the car and allow to run to normal temperature. Turn it off, let it cool down and check the expansion tank level one last time.

[@juantorres943]

Thanks for this ! So I'm not sure yet, do we need to completely remove the bleeder screw the entire time or just loosen it ?

[@AKCD35]

So you could do this when the engine is cold?

[@Obscurewindow]

This worked perfectly the Revs really got the air out of it. Finally - 1995 325i

[@djayk9692]

Gabriel Mendez glad it worked out for you! My son sold his 328i we worked on during my original post.

[@djayk9692]

Ivan G not sure. You could squeeze the hoses to get the air bubbles to the bleeder screw. But the action could draw air back into the system as the hoses relax from squeezing. Thus getting air out while the engine is running/warm was best for our 328i back then.

[@MIRACLECHEEZ]

another trick for you guys to speed the process up. i’ve replaced the radiator and bled it twice in the past 6 months of owning my e36. After reinstalling the radiator, remove the top radiator hose, twist it so it points upwards (loosen the clamps, don’t tear your hoses!) and put a funnel in it. start filling, let the level drop in the hose until you can’t fill anymore. you may spill some coolant here and there. there is a small hole in the t stat housing that allows coolant to bypass the thermostat and enter the engine and lower rad hose. not sure if this is a common thing to do on any vehicle, but i haven’t seen it on any e36 coolant flush diys.

[@MIRACLECHEEZ]

also, if you’re going for an all aluminum radiator, go with koyo over mishimoto! i’ve heard a lot about reliability, haven’t owned a mishimoto personally, but i know many prefer koyo and i like playing it safe. keep an eye out on ebay, you can get one for 40-50 over the price of a mishimoto, and sometimes even less. price difference = minimal, reviews are much better.

[@thomasrobinson3077]

Hey i left my engine running for about 10 mins and no bubbles, i turned the heater on too Does that just mean theres no bleeding to do?

[@agustinpizano5201]

Thanks for the help! Worked like a charm in my 95 M3

[@string2155]

I keep hearing not to let the water pump run without coolant for it would break its mechanical seal. So how does it survive in the initial start up while the t-stat is still closed? I’m also clearing out the old coolant thru distilled water dilution method (several cycles and drain until clear), how do you ensure not to introduce cold water to a hot engine which could warp it? Thanks in advance!

[@MitchellBrown1]

Thanks for this. I've been leaving the reservoir cap off until I see the coolant level rise to the point of almost overflowing before I tighten it. My thinking is that it's an effort to remove the air pocket there too. Does that actually do anything?

[@e36fanatics29]

When I open up the bleed screw I actually leave the reservoir cap off for several minutes until the coolant starts to get very hot. For me its more to watch the level if I've just re-filled it, but I believe it definitely helps with getting the air through the system as well.

[@SteveDurocher]

Bien expliquer bonne image façon simple et efficace... Merci beaucoup !!!👊🏼🤟🏼👊🏼

[@ThugzBunnyYT]

So this is gonna sound silly me and few buddys are quite familiar with this system but we a 328i and we can’t get the coolant system to bleed or I thought it was bleed but we arnt receiving any heat in the Cabin

[@fluent_In_finance]

I accidentally did this to my 98 328i only difference is heat was 90F with that circulation button on while I was driving (cause I couldn't figure out y the heat wouldn't work) then it overheated lol had to wait until it cooled down then added water to the car then it was fine again but i'm concern because it never overheated before..😓.

[@freerats3370]

I dont recommend using defrost, you want it on cabin

[@matrixscutari]

why to turn on the heat? what is the purpose?

[@dukehoughton3934]

Hiya matey thanx for the video... Have a 318ti 1997 heater goes cold when on full have had it ages and never bled... Parked it so my front two wheels were on the kerb... When i open the bleed screw after the thermostat kicks in the liquid disappears... Should i do anything... Any help would b great cheers

[@42-BMW-M57]

I Have Bmw E90 2006 330D M57306D3 with mechanical water pump + Auxiliary water pump Can I do the same method or not

[@96ej]

awesome video, i needed this for my stupid e39

[@magg93]

It's not stupid, just poorly maintained..

[@96ej]

@@magg93 lol I had just picked it up a week before this comment. Got it all figured out. And you're correct the guy before me did not maintain it

[@richardbates4137]

This was helpful. I only had a couple of bubbles come out then it just started boiling out of the bleed screw opening! I replaced all of the typical coolant system bits a couple of months ago, but find that the car still overheats within a few miles...and I get absolutely no heat out of the heater with the blower on high and temp set to max. even with the coolant temp to the red light. When I shut the car off at this point, the cooling fan is off as well. With my 2000 new beetle, the electric cooling fan runs for several minutes after being shut off in the driveway. The cooling fan does run, but the speed seems to be constant. It is almost like the coolant is not being circulated? hence complete lack of heat from the interior heating system? What am I doing wrong here? New to the E36, but it can't be that complicated?

[@e36fanatics29]

What exactly did you replace? I assume that you already checked how much coolant you have and theres no leak. Does it overheat all the time or only at city driving (under 35 mph). They aren't to complicated but they can be tricky.

[@richardbates4137]

I replaced the water pump, housing, hoses, thermostat, belt, reservoir, bleeder valve. I have only driven it around town at mostly under 35, as you said. A couple of times up to 50...seems to run fine at that, but at the red light, heats up again. And it doesn't put out heat from the heater either? Coolant level seems to be ok and there are no leaks visible?

[@e36fanatics29]

Run the car at idle, have someone watch the coolant gauge on the inside to make sure it doesn't overheat to much, get a hand on the return hose from the thermostat housing, as the car hits the middle on the gauge it should start heating up. This means that the coolant is circulating and the thermostat opened. If the hose doesn't get noticeably hotter to the touch the thermostat probably isn't opening. Second idea: Fan Clutch, the engine driven fan has a clutch inside it that is supposed to tighten up as the vehicle heats up, this causes the fan to turn faster, you can google "fan clutch newspaper test". If your car is overheating that quickly I would start with the first thing to make sure that the coolant is actually circulating, especially if your coolant level isn't dropping.

[@e36fanatics29]

I had an overheating issue a few months ago after I changed out all the typical parts on the coolant system. Turned out in my ignorance I neglected tightening the lower radiator hose enough and it was leaking, tightened it up and problem was solved.

[@richardbates4137]

Thanks for those ideas. I will try them and let you know.

[@JZXVecca]

What if coolant keeps coming out of the bleed screw?

[@joelthepizzawizard493]

im confused as to why you lifted the car. Is it to have the coolant not leak as much?

[@Chattsteezy]

Gets the radiator and hoses higher then the heater core which is the weak part of these systems thus forcing the air to the top. Works for some doesn't for others. E36 cooling systems are hell to deal with. Good luck

[@beastmonster7306]

Good job mate 👍..

[@BrittneeWiliams]

Thank you

[@rhenzpuno9277]

Where do I get the screw for valve cover gasket my guy? It’s leaking I need to tighten it but it’s rounded

[@dwayneharris1026]

Hey Steven do your have a video on flushing the coolant on a 1996 bmw 328i? Thanks

[@andrewj325]

I tried your method and the bubbles never stopped even after an hour.

[@willriseabove6858]

I've got a 01 325i and theres steam coming from the radiator connecting to the top hose of the resevore at idle. I've looked into it an it can be heater core, head gasket, thermostat, or water pump any way to narrow this down or your opinion?

[@juantorres943]

Is the heater on the entire time? And do you know if the steps are the same if you have a mishimoto radiatior with the expansion tank? It has the bleeding valve as well.

[@e36fanatics29]

Juan Torres Yes, and I'm not 100% sure to be honest haven't owned one before, should be the same.

[@harmonistallings492]

Thanks, this helped.

[@e36fanatics29]

Happy to help!

[@robertbawden1702]

please help me now. 1996 e36 323i. did the coolant change and followed your direction and now its boiling at idle. right hand radiator hose cold. left radiator hose boiling hot. radiator/expansion tank full and bled properly with elevated car and heaters on. south east western australia. please help. this car has never let me down. can someone please tell what is wrong.

[@e36fanatics29]

If the other radiator hose isnt getting hot once the vehicle hits optimal heat and if its passing optimal heat sounds like the thermostat is not opening.

[@e36fanatics29]

Obviously can't be 100% certain, but from what you said in this description this would be my best bet.

[@robertbawden1702]

thankyou sir. all new parts. im a qual mechanic. i noticed the cooling system is a bit differant that was all. hasnt it got a releaf valve or bypass for extreme situations like this. like a hole in thermo to equalize pressure. tar mate. if it was horse i would have shot it by now piece of shit.

[@e36fanatics29]

No, I have never heard of a plug in the thermostat housing on a bmw, possibly on the newer models, but certainly not on the e36.

[@Twinkletoes1O1]

Hello how long do you think this should take. It’s been an hour and a half and I still see bubbles coming out?

[@e36fanatics29]

Takes me about 10 - 15 minutes.

[@Twinkletoes1O1]

Oh okay, I’m using 100% distilled water bleeding the system. Do you think that the water is turning to vapor bc of the lower boiling point?

[@rantefrmpelican5133]

Does this work with 1999 323i?

[@rogertorrez1798]

Should I be loosing coolant from my expansion tank?

[@UKDrew]

yes its a factory upgrade ^^

[@breannewilson1]

I just had hot coolant seep out out the coolant cap, while its tight shut. Same thing with it off. I ran the engine during all this and I don't know what to do. I hate the cooling system in these cars. I don't know how to bleed these things. All I got was hot air coming from the bleedscrew. NO hot air from heater. I just redid everything in the cooling system.

[@e36fanatics29]

First thing is I wouldn't fiddle with the coolant reservoir cap while the engine is still hot, the coolant is pressurized. Once the engine cools off take a look at the reservoir cap area, if your sure the coolant is coming out of there and not a crack in your reservoir tank or coolant just seeping out of the bleed screw area, than I would take a look at the threads that the reservoir cap screws into, and if everything checks out I would go get a new reservoir cap if it appears damaged. If you have no hot air from the heater that's no big deal, its just something to help circulate the coolant through the system.

[@e36fanatics29]

Oh and last thing! Make sure the coolant isnt overfilled, theres no way of telling this until the engine has cooled.

[@breannewilson1]

Thanks, I overreacted and over thought it. E36 Fanatics It was pretty full when cold, I kept adding until it came out of the screw without bubbles.

[@_playboicartimar]

what type of coolant do i use for my E36 316i???

[@langertown]

use the greenish blue coolant that BMW recommends. You can get it at the BMW dealership and some good auto parts stores sell pentosin or Beck arnley, which is the same green/blue. Be careful if you buy coolant at an autozone, the gold/yellow coolant they sell as 'BMW' is not compatible

[@e36fanatics29]

Its highly recommended to put pentosin or Beck Arnley.

[@Kenai8000]

Mother's milk

[@EseManiak]

Wait I have turn the car completely on? I thought we just turned on the electronics..

[@e36fanatics29]

What model bmw do you have? Some of the newer models have electric water pumps which have a different process.

[@EseManiak]

E36 Fanatics I have a 1999 convertible 323is

[@e36fanatics29]

Yeah, it has the same coolant system as this one.

[@EseManiak]

E36 Fanatics so I run it till there's no longer any bubbles, with or without the cap on the radiator reservoir tank?

[@e36fanatics29]

Pop the cap back on as it gets hot, or just keep it on. I pop the cap off initially to speed up the process. If there is a lot of air in the system as soon as you loosen the bleed screw you will hear air rushing out.

[@Aigentcy]

how much coolant?

[@ashergrosfeld9017]

mines steaming and above normal temp

[@DeveroyB]

I have this exact model same colour morea groenen

[@richardorosco7936]

Can someone tell me why you have to bleed the system. What happens if you don't

[@e36fanatics29]

You bleed the coolant system typically after you have done a repair on the coolant system, this is because repairing the coolant system such as replacing a thermostat or water pump introduces air into the coolant system. Unfortunately bmw's are not like most American cars where the coolant reservoir sits above the radiator. American cars are typically "self bleeding", because air comes out through the reservoir, not the case with BMW's. If you don't bleed the system, it can cause the car to overheat due to an air bubble stopping the flow of coolant.

[@richardorosco7936]

Thank you for the information and i hope you have a blessed day Thanks

[@e36fanatics29]

Thank you and hope it helped!

[@charliejones7262]

Richard Orosco

[@Yophillips3272]

You won't have any heat and your car might overheat.

[@sanjel07]

Thx 🇨🇦

[@jerolvilladolid]

It works!!!

[@pbmig]

Can this apply to my 318is m42 e30?

[@e36fanatics29]

If I recall correctly yes, because the e30s have pretty much the same sealed coolant system.

[@LuisPadilla-fq4co]

awesome

[@e36fanatics29]

Thanks!

[@trashheap5590]

My heater doesn’t work 😂

[@bobbobby1412]

This assumes the coolant system is empty. What if it already has coolant in it?

[@e36fanatics29]

Bob Bobby same exact procedure

[@ericbranch1830]

What if I can’t turn on my heat ?

[@e36fanatics29]

No problem, if you get the heat working again and it's not heating well bleed it again.

[@davestlc1]

@@e36fanatics29 the heat has to work or you may never get the air out the engine which could damage your engine

[@inmortem]

I did this all & my check coolant light came on again

[@e36fanatics29]

that "check coolant light" comes on when a floater in the reservoir drops to low. The floater is made of plastic and frequently breaks apart, leaving your check coolant light on at all times.

[@jazminpolanco5771]

La informacion que se necesita saber de un auto Bmw esta en ingles y yo lo quiero en español

[@jazminpolanco5771]

La informacion es del termostato del Bmw pues el auto se le sube la temperatura

[@racingrival4528]

@@jazminpolanco5771 yo hablo los dos, te ayudo?

[@donshilo2024]

Really you just open the key heat and fan on for 15 min and will do it on its own.

[@davestlc1]

engine has to be started if your flushing or have had to replace radiator resevior or hoses ect. and lost to much water the water pump has to engage. if you have one little air bubble anywhere and fail to catch it in time could cause major engine damage. take your tie do it right and save yourself in the long run. and if your a service tech where do you work? so we can avoid that place.

[@jamesadams934]

30°😳

[@soccer19942]

worst technique ever lol

[@e36fanatics29]

thanks for the comment

[@soccer19942]

anytime

[@rabeenemer]

"shut the car off, set it down, and then trade it for a Civic"

[@zoxsk8]

Yeah these cars suck. I have a civic, E36 and a GT86. The E36 truly is a piece of shit car, the headaches never stop

[@rarefruit2320]

Wtf 😂

[@DandyWaves]

Lmao fuck a civic

[@karimickey]

Man every month I have a new problem with my e36 lmfao but I love this car I do want another civic tho

[@mul555]

I've got a civic and an E36. The E36 was my dad's, he's passed. It's the funeral tomorrow and it'd be nice if the car makes it. I've had it 3 weeks and it's a money pit with only 70k on it😅

[@KWN-Cards]

My god, get to the point!

[@fuadbrenner8885]

What's the reason for lifting the front, I just tokk offy watsrpump and found that water has never went through my block, what can be the cause of that plz any1 I need advice, my car was over heating after replacing the cylinder head

[@midgemaniaflyfishing]

Don’t know about it specifically I’m trying to get some info currently on a e39 but the reason I assume he is doing this is because it is the procedure for bleeding a e30 because in that you need to raise the bleed screw/ tstat housing making it the “highest point” on the system so that when you’re bleeding and filling there aren’t any bubbles trapped somewhere along the way