Why You Should Never Remove or Use a Colder Thermostat In Your Engine.

[@KevinJames-yg9eu]

As a former OEM truck engineer responsible for validating Caterpillar and Cummins cooling system installations, I find the ignorance of some of these comments astounding. I agree with most of this video. Here are a few points to clarify the video and the inaccurate comments. Removing the thermostat can make the engine overheat, not run cooler, because the lack of thermostat means the bypass isn't blocked, so you're splitting coolant flow between the bypass and radiator instead of sending it all to the radiator. To those of you clinging to the myth that coolant flowing "too fast" doesn't have time to cool off in the radiator, well, then it also doesn't have time to get hot in the engine. Heat rejection is the flow rate times the temperature change, and being a closed system, the temperature rise across the engine has to be the same as the temperature drop across the radiator. There is no such thing as coolant flowing "too fast", but there is such a thing as too slow, where the boundary layer can boil on the heat source or not transfer heat efficiently in the radiator. Boiling coolant on the heat source can cause erosion and/or cracking. At a given operating condition, the engine always puts the same amount of heat into the coolant. The coolant will get as hot as necessary to expel that heat into the ambient air via the radiator. If you have a fan, radiator, water pump, pressure cap, or recirculation seal problem, a thermostat doesn't fix anything. As the video says, the thermostat controls the engine's minimum operating temperature. It has nothing to to with the cooling system's ability to reject heat.

[@AdeptApe]

I pinned your comment to the top, very good information there, especially the bypass and coolant speed. Everyone should read that.

[@FixItStupid]

That's Right Thank You

[@misters2837]

I would add, the thermostat blocking the bypass is on "some" cooling systems certainly not all. BUT it is a valid point! *ALSO MAKE SURE YOU HAVE THE CORRECT THERMOSTAT STYLE* (For the Bypass to WORK/BLOCK properly) - Also that myth that Coolant is moving too fast when there is no thermostat is reinforced by people who have had their lower hose "suck flat" and didn't realize it. They are same crowd that thinks Chrome Valve Covers hold in heat. - Removing the thermostat will "usually" increase the speed of the coolant in the system, slightly increasing the "cooling capacity" of the radiator, and on a system that it is failing (overheating), it is a temporary Band-Aid, because your radiator/water pump has diminished capacity (or you have turned up your engine too far for the cooling capacity it was built with), and the slight flow increase will only make up the difference for a short time, until the Rad/Pump/Fan Clutch fails to cool the btu's that the engine is rejecting. - On our race cars we use tape to block the cooling air and do not run a thermostat, for several reasons...Mostly Aerodynamic (Tar Track) and Mud/Dirt Packing (Dirt Track)...But the cooling system is almost undersized (weight) and the faster coolant in the block keeps hotspots from forming...(The engine really runs good at 220-230°F but has extra clearances to not stick a valve or pinch a ring.)

[@lonetraveler5660]

Not sure about other cars, my Volvo mpg improves once I replaced broken thermostat. Stuck open thermostat let coolant run through the engine all the time and take longer time to reach the optimal temperature. Working thermostat let coolant pass through engine when it needs cool down. The car will reach the optimal temperature before heatjng up whole coolant.

[@RB-cz5jn]

I enjoyed you comment. The cooling system as a whole is designed to cool down the engine. Thermostats hold the heat in the block until they open up on a diesel. I ran a 3406b for over 2 yrs with broken thermostat (rare reason why). I figured I would just run it until she blows. Wouldn’t ever reach temp unless on a hard pull. So why then the different thermostats and why the different sizes of radiators. I can tell you but I’m barely a shade tree mechanic. Your reference is right but wrong. On a hard pull you need time Edit: I will not run a truck of my own without a fan on off switch. Reasons for this. Your argument maybe the cooling system is working right. My argument the load is hard to pull the hill.

[@badgerpa9]

Newer engine tolerances are designed so it does run hotter for fuel economy and better burn of any sludge. The " I have been doing this for 30 years" person shows they know very little about the past 30 years and that there are many changes in the past 30 years. Nice video you explained it well, some will not believe it. Some manufactures run different temps in some extreme environments. In the far north of Sweden, Norway, Finland you can get cold prep package designed for the north that will include a hydronic heater to keep the engine temp hot enough. Stay safe and healthy Josh.

[@RB-cz5jn]

Caterpillar stopped making over the road engines in the states I Beleive in 2010. Google sensors on any of the new engines. Oil and type of oil is a big deal.

[@606budwheel]

burn off sludge? really? where is this sludge? I`ll watch for it next time I`m driving my truck in northern Sweden or Finland or uranis

[@badgerpa9]

@@606budwheel Stick your head up uramis and see. I am sure you are smarter than any toyota engineer you probably even passed 1st grade. Since you know nothing about engines I will point you to what used to be a breather and voided fumes and unburned hydrocarbons in the air but now recirculates it into the engine. Some even put catch cans on them to collect the sludge. You showed you know nothing about engines and are a buffoon even a lawn mower tech knows about fumes not being voided in the air anymore.

[@badgerpa9]

@@606budwheel I bet you believe everything scotty says don't you?

[@jasonwakewich121]

Dosen't burn off sludge!! If it did it would cause carbon deposits. It evaporates the water in the oil before it can mix with the oil to cause sludge to form or chemical reactions. dont be a smart @ss and talk down to people try to educate

[@dextermorgan5329]

Greetings from Turkey. I'm a Service Engineer in Komatsu Heavy Equipments. You explained very well. I have completed my deficiencies. Thank you sir.

[@terryfrederickson2774]

as a ASE master tech, I'm glad you did this video, it dispells some myths of cooling systems. I mite also add that the thermostat also is a flow restrictor that prevents excessive pressure surges to hoses and coolant system at high rpm. I am always amazed at mechanics that believe that removing the thermostat will make the engine overheat ,, just amazing. but then some people still think the earth 🌎 is flat

[@termonostruman]

thetat becuase hes not a mechnic,, if he dont knows that hes not a mechnic..

[@rbmccloskey]

I had a overheating problem with my Caterpillar 977L with a 3306 engine. Was advised by several people, including two mechanics, the problem was: a) bad thermostat; b) blown head gasket; c) low liner projection; d) bad or clogged radiator; e) bad water pump; f) motor needs to be rebuilt and several other silly ideas. The problem turned out to be the radiator cap was not maintaining the necessary pressure in the cooling system, it was releasing at 5 psi. I replaced it with a new Caterpillar cap and the engine runs at the correct temperature ever since. The moral of the story is, try the simple things first.

[@BeardMan01]

As a certified forklift operator, you're almost all the way correct. The things that you're not completely correct on, aren't really worth bickering over because you covered almost everything. Good video man!

[@jamesgeorge4874]

Solid advice that applies to everything liquid cooled. I start every overheating diag with a combustion gas test, right off the bat. Bought a quality tester and several bottles of fluid. It confirms a base engine issue, that needs to be confirmed as good or not good before proceeding with an overheating concern.

[@deezelfairy]

Another point with removing a thermostat being a bad idea is the flow restriction the thermostat creates is what forces the coolant to flow around the back cylinders in some engines - remove it and you can end up cooking them. Thermic lancing is cool, I once spent two days trying to slug out a 3" diameter 12" long bucket pin out of a volvo loading shovel, even with oxy acetylene equipped with a 4" rose bud the most I moved it was 1/4". Customer knew a guy who did it, my company begrudgingly agreed to get him in. He was there in an hour and the pin was out, new pin installed with new bushes in 45mins, guy charged about £250 - mind blown! 😂

[@darinareyacrazyman1505]

Correct, it also has to do with time. Coolant needs time to absorb heat and carry it away, removing the restriction causes a higher flowrate, but less time to absorb.

[@misters2837]

@[Gaming Channel] The Eastern Bloc Brainlet Q Exactly...Put your hand in ice water and hold your hand still...Then do other hand and stir the water with your hand...time how long you can tolerate both! (Moving water takes a way heat faster, as long as its not aerated)...Divers in the Cold Ocean, have come to dive in our Rivers in winter time... They talk about the currents in the river carry away body heat faster than the tidal currents in Ocean...

[@deezelfairy]

@[Gaming Channel] The Eastern Bloc Brainlet Q Yup, the lower the temperature of that coolant when it enters the rad, the cooler it going to be when it leaves it. The faster the flow the better and as you say, the bigger the temp difference, the quicker the heat transfer. Also an overall higher flow rate system allows far more margin for problems with the cooling system if things do go wrong. My point was more about the flow dynamics around the cylinders rather than heat transfer overall.

[@Faolan161]

@@darinareyacrazyman1505 the greater the difference in temperature of metal and coolant, the quicker the transfer of heat. Your perception would be true if the coolant were to only circulate once at warp speed, but that's not the case. The coolant stays in the engine plenty long enough for heat transfer to take place.

[@abpsd73]

Another problem with an incorrect or removed thermostat is with all the computer controls on the engine. Most ECUs will run different timing/fuel delivery until the engine is at what the computer considers operating temperature, so power output and fuel economy will suffer.

[@corywillbanks6348]

In the Cat cooling system A&I guide I believe it’s stated that the thermostat determines the engines minimum operating temperature and the cooler/radiator determines the engines maximum operating temperature.

[@larsbkurin1740]

It must be for educational reasons CAT writes like that. The thermostat has several tasks, reduce the warm-up time at start for both the engine body and the oil as well as the rules in chilled water from the radiator to maintain the designed temperature of the engine.

[@quewat3676]

This guy is dope...i have a ddec 4..and i still relate to the knowledge he offers

[@duncandmcgrath6290]

It’s frightening how much I’ve learned from your channel

[@flipcacau]

Best diesel/automotive channel on youtube. Great video

[@AdeptApe]

Thank you.

[@larrytalley117]

So glad to see you back on here. Love your videos.

[@baileysomers9142]

Keep up the great work josh

[@jesust6101]

I replaced 180F with 160F and my Detroit engine fan programed to kick on at 205F. Over 700k miles that engine have not given problems and fuel economy have increased since it takes too long to go from 160 to 205 for engine to heat up. Nonetheless engine oil runs slightly cooler and engine sounds happy and feel more powerful.

[@garykirk1968]

Thermal Lance was a brand name that became existent amongst all of it's kind, like "Bobcat" when referring to a skid-steer. They are "exothermic" torches, the old thermal Lance required pretty much a heavy duty welding machine and some other stuff. The newer exothermic torches you can use with a 12v battery and an oxygen cylinder. I'm trying to get the company I work for to buy me one for all the seized pins I get to deal with on our rental equipment. ETA; I am THE welder, but also a mechanic, elechicken, air service guru, have pretty much become one of the "go-to" guys about everything.. And I deal with most of our sales trucks/equipment at some point. LOTS of Cat stuff comes through, and I appreciate all of your videos brother. You've helped me out on a couple things that had me pretty stumped.

[@rustypotatos]

that shit was fucing awesome man

[@Fatamus]

Slobber'r A.K.A. 66 Ford F100 always ran 160*F till I put in a 195*F ... Ran so much better and way better fuel economy.

[@tangydiesel1886]

Seen the same thing. 64 ford 292. Ran like junk until I put in a 190 back in it. The engine overhaul showed it as well.

[@TheBandit7613]

I ran a180 degree t-stat instead of the 195 I look 30 minutes from Death valley. Works great

[@jbtOO7]

I agree lower the coolant temperature also in my opinion the factory radiator will be more efficient at a cooler temperature but need to change the fan engagement temps to match the new thermostat setting.The average temperature around you vaporizes moisture all your doing is making sure that because your in a much higher temperature climate where the factory cooling system can only handle so much and in my opinion the temperature rating is for colder temperatures and with your average temperatures being extreme means the cooling system is always at the upper limits at what it can handle and moisture retention is never a problem but running in critical temps all the time is. So it's not just enough to have a lower thermostat setting but the fans also adjusted so that the radiator doesn't fail to keep the new temperature setting in place.But your not delaying eventual temperatures but keeping the temperatures right where you want them to be.And I would also like to add that the factory radiator will work better than intended because the factory radiator can easily cool off lower temperature setting versus critical temps you might be able to bring the temperature down with a factory set up and factory temps but the oil temperature will be boiling over regardless. So like a runaway effect that is primed and ready by putting a lower thermostat setting there is no runaway temperature fluctuations waiting to happen like just a few temperatures away but by 30 degrees cooler.I think your right and would be doing the same thing.But also there has to be in the new models a computer adjustment to say the lower temperatures are ok as well. There is hardware and software available to reprogram the on board computers.But that has to happen along with the other changes to be effective and without a problem it will be smooth sailing where do you live and that's a beautiful thing.

[@brandonburdette7895]

My one owner 91 s10 has got 242,000 miles I use it every day I would trust this truck to drive across the United States any where I've had my thermostat out for about 6 years and it hasn't had one single problem I still run the green coolant as well maybe one day it might show its self but this truck is the best running truck I've ever owned and I wouldn't sale it for nothing

[@johnstamper2965]

How is your heat in the winter?

[@jameschristy9966]

I put a 160 in my mustang for racing years ago nothing happened but he is probably talking about new cars

[@misters2837]

@@johnstamper2965 Well considering he said "Sale" vs "Sell" I would assume that he is south of the Mason-Dixon line, so likely not an issue as they have no idea what Cold is. Also the only reason that he doesn't get a SES light is because the TBI Fuel System goes into closed loop at very low temperatures. But I can tell you that the power might be a bit better running cooler temps...but the MPG on that truck is trash...Having owned a TBI GM Vehicle myself and the Thermostat going bad cost me 3mpg (considering 15 was a good trip that's BAD) in mild Fall weather...Didn't really notice a big difference in summer.

[@Force1Com]

Slightly lower temp and so much sh1t actually lasts a lot longer that at 210/220

[@tangydiesel1886]

Depending on the engine, removing the thermostats can cause overheat much quicker. Some thermostats redirect coolant when they open. So without them coolant can just loop in the block, and not make it to the radiator. Other thermostats direct coolant to the oil cooler, so the coolant can be very low, but the oil temp will get way out of hand.

[@user-uj3zk2cx8t]

That's a myth

[@termonostruman]

SHUT UP

[@donaldappelhof2059]

I had a friend that put a warmer one in his Ford pick up and it caused problems with the computer when ever he towed his trailer. After taking the truck in to three different shops and a lot of parts replaced after a year later they figured it out! Stick with what the factory tells you!

[@OGbqze]

Stock rocks.

[@matthewmarquette6778]

I was taught and have seen it that a thermostat slows the velocity of the flow to give the coolant time to transfer the heat while in the radiator to the air

[@misters2837]

Osborne Reynolds would disagree...The faster fluid flows, the more turbulent it is, resulting in HIGHER thermal transfer...However the water pump must be of a design as to not create cavitation, which would be counter productive.

[@pr0n5tar]

That person told u wrong

[@misters2837]

@@pr0n5tar What Person Told WHO Wrong?

[@dennisford2000]

Wrong.

[@daviddroescher]

When my oil cooler failed in my '91 Dodge I researched doing an oil cooler upgrade instead of doing the repair. The information I found on the subject was that early on they used a 9 plate industrial cooler. Cummins found the oil was not maintaining proper temperature(over cooling) causing the volatiles to condensate and do the damage you have described. They changed to a 7 plate for the automotive 6bt and a 5 plate for the 4bt to solve over cooling.

[@SP-mp9yi]

Agh great research this was my question about generic aftermarket oil cooler's. "Increase your oil capacity" claims might not be the answer then. Maintaining optimal operating temperature would be very specific to each vehicle on how that can be achieved. Wow simply 2 plates off the cooler on yours was enough to be an issue. I'm glad I caught this because I was that guy who thought cooler was always better, all the internal parts in harmony is the proper goal. I'll scratch the extended oil line running through the AC blower plan. Lol 🤣

[@daviddroescher]

@@SP-mp9yi 134a cooled oil would be awesome so long as it had a thermostat like I'm running on my ATF it's 160° mishimoto bypass thermostat plumbed in - 12. My Allison requires a minimum of 148 to allow shift trim adjustments anything less than this the transmission expects wonky viscosity results therefore prohibits shift trim adjustments making the first run through the gears not so great.

[@Fabien2626]

I've recently done the opposite, I used a hotter thermostat as I discovered, in my particular engine, in the winter, the engine took way too long to heat enough to help the water evaporate from the oil.

[@phprofYT]

A better analogy would be the human body temperature of 98.6F. We don't work well much below or much above that temperature. When we feel hot we perspire more, seek shade, a fan, A/C, etc to assist in our bodies natural thermo regulation system (thermostat). Same with being exposed to cold temperatures.

[@TheBigdog868]

The "30 year experience" part made me chuckle. I know a guy who says that but what he means is he has one year of experience 30 times. Hasn't kept up with the changes or tried to learn anything new.

[@crusiethmaximuss]

That last tool reminds me of an old school carbon arc gouging machine I used at a welding shop I worked at a decade ago. I actually prefer some old school equipment like a Sun VAT 40 battery tester or carbon arc for big stuff instead of plasma

[@keyboardplayerakas]

If you were interested, it would not be legal to thermal lance kingpins out in new Zealand and Australia, as we are not allowed to heat steering components at all. If they don't come out we pull the axle and put them in a press

[@misters2837]

That is INSANE! - I have used a torch on king pins to warm the rock hard grease and melt it out so new grease can be pumped in...Almost a daily task when working on Vintage Trucks.

[@jimmotormedic]

I believe that, any mechanic that has seen a twin I beam front axle on Ford truck of any era has seen (DO NOT USE HEAT) in raised letters on the beams. I have also seen it on other medium and heavy truck steering axles. I will admit that I have had to ignore that warning many times. In the rust belt the most important tool to have is a good set of torches!

[@oby-1607]

@@jimmotormedic It says Do Not Use Heat to re-align the axle. Meaning do not heat to the temperature where the axle glows red or yellow so you can bend the axle for alignment. Minor heating to allow grease to flow is something different.

[@firstlast---]

@@oby-1607 You are correct

[@harttrusty2185]

I’ve got a marine 160 that was also designed for this engine so I think it’ll be ok

[@brentmcmahon8188]

My 1992 Dodge 5.9 came out with a 180 thermostat and my 05 came with I think 195 and these trucks have a problem with number 56 cylinders getting too hot so I just put a 180 in to keep more antifreeze movement threw the head and a by product is that you heater is blowing hot air out of your heater about 3 times as fast.

[@PickupsAreNotTrucks]

Hey Josh. I did kingpins on my W9 and one of them developed a burr while still in its bore and locked up tight. Ended up having to pull the axle out and take it to a machine shop where they had to use a 150 ton press to push it out. What a nightmare those things can be!

[@keyboardplayerakas]

How often (miles) do you grease them? Never had an issue here in New Zealand but companies are basically required to have trucks greases every 15,000km or they void their insurance

[@PickupsAreNotTrucks]

@@keyboardplayerakas I try to grease my truck every 5000 miles or max 10,000. I bought the truck with a bad kingpin.

[@MyKharli]

Mine had to be heated to near melted with a 150 ton press , It ruined the hole so i ground off the axle end and welded the new ones in , they lasted to the end of vehicles life . Mostly overloading and very high mileage had welded them in .

[@PickupsAreNotTrucks]

@@MyKharli goodness gracious. What a nightmare. Great job overcoming! Replacing the entire axle ain’t cheap. I know cuz I priced it out.

[@MyKharli]

@@PickupsAreNotTrucks They are silly expensive and second hand ones have the same fault imo . It was hard ensuring the kingpin was correctly aligned and keeping the top surfaces clean and flat . TBH i was always sightly worried the weld would crack off even though i did a beefy job . It passed the MOT for many more years though . TY for reply .

[@seekingtko3146]

combustion engines do run better if they are allowed to run on the high side of the recommended temperature stats.. there's alot to be said way too much for me to type in ,but your right.

[@tangydiesel1886]

That's why the air cooled deutz engines where so efficient. When you're not worried about boiling coolant, you can let the cylinder temps get a whole lot hotter. As long as the oil is kept in check.

[@jesusyuca1483]

I just want to add that some engine designs fail in a interesting way. The best example is the jeep 4.0 6 cyl inline. People have always had trouble with the thermostat being laggy, slow or delayed. A thermostat opens depending on its rated temperature. However some engine designs have the thermostat housing way to close to the fan. This will cause a pocket of cold coolant to remain around the thermostat making it hard for it to open. The best solution is to make a tiny hole or remove the metal piece that blocks the hole on the thermostat. Having a little flow always will stop that pocket of cold coolant from forming thus your thermostat will respond much better.

[@SandersChicken]

Haha I did this same thing to my 89 XJ and it fixed all my problems. Just gotta make sure it's a tiny hole!

[@jesusyuca1483]

@@SandersChicken Still waiting on a punk who thinks he knows it all to tell me I can’t do that. There are so many different theories around the cooling of that engine that frankly don’t make sense. Some people don’t notice they started having problems with the thermostat after upgrading fans.

[@misters2837]

@@jesusyuca1483 The burp/trickle hole has been around as long as the thermostat itself...300 Ford six has similar issues. - GM in the late 80's and Early 90's went to the extreme with similar idea... 87 G20 350 V8... With the thermostat closed the coolant within the engine was circulated thru the heater core, and rather than keep recirculating that same coolant until engine got warm, the dumped the outlet of the heater core directly into the radiator...It had the same effect as a normal system with a "stuck half way open thermostat" or a 1/2" Burp Hole! - Took forever to warm up from COLD...SMH! - I remember my father putting a 1/32"-1/16" hole in the stat of his 300-6, he was a troubleshooter for Ford's warranty program in the 70s...the guys that write the TSBs because of field complaints...He said you need enough to piss thru there, not so much it cools the engine... Some of those engines would have benefit from the dual stats used on big trucks, you could have different 2 temps for variable cooling...like dual fans on newer cars.

[@jesusyuca1483]

@@misters2837 I appreciate the comment. Obviously having a peehole on the thermostat makes complete sense if you want a simple yet effective design. How else are you going to get the best results to keep the thermostat getting hot water straight from the head to get the most accurate moments to open and close. That is why newer cars have such complicated designs and honestly I don’t think they do such a good job like a simple hole does. The only set back is the slower warm ups.

[@johnjones1812]

I have owned over 15 vehicles throughout the years, I have killed one engine from repeated overheating all other vehicles I remove thermostat. No one has managed to convince me otherwise. I got my view from my experience with one of the most bulletproof vehicles I own 80 series land cruiser. It was manufactured with a oversized radiator and temperature gauge never reach half, everyone stand by the durability of these vehicles, I might be wrong but I never encounter any issues so far.

[@tihspidtherekciltilc5469]

I worked on quite a few cars in the 80s and 90s where the drivability issue was lack of a thermostat for "racing." Not having that restriction can also create localized hot spots due to inadequate flow and cavitation.

[@johnbelwell2461]

You can run an engine with no thermostat for as long as you wait for parts to arrive as it's better to have no thermostat than a stuck one, but there's no point as if the engine overheats there's a problem hidden somewhere else as the thermostat opens at a temp way before to the point it overheats. Under load the engine keeps its coolant temperature very stable depending on the fan settings and the cooling system design, so you can say the thermostat is almost useless, but in cold mornings and light load it's where you need the engine to become hot as soon as possible to have the oil and the engine work at a high efficiency as that's where wear happens more quickly.

[@davidclough3951]

Once a ran a car in hot summer on a thermostat that the insides came off, while it was installed on the engine. Didn't bother replacing until the days started getting cooler. I would think running a cooler thermostat in cold winter would actually help the engine warm up a bit faster as the coolant would stay in the radiator less. But regardless once the engine is up to temp I would think the thermostat would remain open regardless.

[@homuraakemi9556]

It really depends on the conditions in which you're driving, I think

[@darrellbedford4857]

Another reason not to run the engine cooler is the oil viscosity. If the oil is cooler than it should be the oil pressure will go up and its ability to drop contaminates will also drop. So you have dirtier oil at a slightly higher pressure going through the bearings and possibly scoring them. The oil pump will have to work harder thus wear out faster and overall use a slight amount of extra fuel.

[@SmudgyContent]

If you have a mechanical fan, KEEP IT AS VERTICAL AS POSSIBLE!!! If you removed it. There’s a liquid inside the fan, if it’s laid down on say it’s face or front, it can leak and contaminate the Clutch in the fan. If this does happen don’t fear. Just tack weld it to its self. Full time high speed fan

[@Jpaydirt]

I had to put a 180 and one 190 in my C15 because with the factory 207 stats my retarder oil temp was at 235 all the time and you couldn't use it, in 20 seconds you'd be over 240 and that's not good. Mr. James says " at a given operating condition the engine always puts the same amount of heat into the coolant" I have to disagree in the case of a CAT Brakesaver. In my case the cooling system cannot keep the oil under 235 with brakesaver use, having the whole system operating at a lower temp. allows the retarder to put huge amounts of heat into the system giving it the ability to stay under CAT's guidence to not allow oil temp to exceed that 240 mark. the other statement he makes I find interesting is coolant flowing to fast, I've seen CAT stuff with restrictors in the stat oulet to the radiator to restrict the flow, I've also seen CAT equipment that they had to slow the fan speed to improve the radiators ability to remove heat, I've even read that from CAT when doing the change up. and experianced it, with the engine at full rpm no load it would overheat in 45 minutes, changed the fan speed and bam! end of problem. the coolant does need to stay in the radiator long enough to reduce the temp on the outlet by at least 10/15 degrees if it's not then it's not your stats but your radiator. I got a lot of guff for getting rid of the oil temp stat in my N14 (plugged Hole) but I still get the oil to 200 and that's high enough here to boil out water, but I may put it back as I have discovered I can get a lower temp stat for the N14 in a farm tractor application, I'd love to hear mr james explain why they would run oil temp above 240 in a truck but not a tractor, not bashing him as tone doesn't come across with typing, love talking to engineers You can learn a lot

[@tdashkevich]

I have staggered 180;190 as well. 800hp cat. I like that during the summer I’m not running against 200 all the time, slight hill and it would go over 200.

[@foxbraap6373]

Great video! I was always skeptical with the 6.7 powerstroke guys saying a must have mod is a thermostat that opens sooner. This seems to prove to just leave it the oem

[@kumakaroshi117]

Make so much sense. 25 years down the road and maybe 7 engines ago.

[@RB-cz5jn]

I’m going to chase this one. But water as mentioned can also create steam in wich can be destructive. The acid build up and all that Josh mentioned is true. I want to see my self through oil testing to see where this goes. My personal experience so far has been good running cooler thermostats. But at what price? My oil samples overall come back in normal range. Going to be interesting going forward. Thanks for the video and thank you for the conversation and the attention it brought. Interesting side note. Water can create sludge in wich can plug oil filters. One way I guess to see if there’s water in the oil is to heat it up to see if it pops.

[@wazza33racer]

Thermal lance is what they use to cut through reinforced concrete and steel bank vault walls. Like electric arc cutting, it makes short work of thick steel.

[@localenterprisebroadcastin5971]

Glad you cleared up this myth …if your engine is over heating you have failing thermostat or something else wrong that needs to be fixed …correctly

[@tylerhall6455]

wow love the thermal lanse at the end! I'm a welder myself, but never used one of these lol

[@baronclime6423]

We had a truck the other day the fan clutch was stuck in the "on" position. Engine wouldn't get much past 100 degrees. Just an aside. I agree don't go to a cooler thermostat. If you have problems yes start with the cheaper option "it could be stuck closed or open" but get in and find out what is going on.

[@daltonbough3302]

Glad you are back been missing the vids

[@samwalker3441]

Good stuff, Josh. Thanks for posting on this often misunderstood topic.

[@justnsaliga8518]

glad i watched the video.... my trucks got stock themostat that opens at 210, i wanted to run one at 195.

[@nunika1975]

I went from a 91c thermo to a 82c and I had a very positive result. Before I was getting 93c to102c temps. After cooler thermo, my temps are 83c to 94c. Side effect also resulted in a cooler running ZF transmission (by about 6c), since coolant also cools auto tranny. This was on an Aussie FORD Falcon FG 6 cylinder Barra located in Brisbane Australia.

[@rustypotatos]

bigger problem then

[@bryanyoung9482]

I did this one time on a 04 ford lightning I swapped the 180 T for a 160 T. The motor did run cooler for a few mins than the cooling system got heat soaked and started overheating this was normally when on the hwy so I put the stock T back in.

[@elijahrobinson2362]

That thermal lance is a serious piece of equipment. Notice the breathing rig work by the welder during use of the lance.

[@wildman9364]

very cool with the kingpins I have had some seized ones had to heat up cherry hot and hammer and air hammer them out seen a few the axle was damaged and had to re-sleeve it. Cheers

[@ra5gto]

The moisture issue you mentioned would be more applicable to engines that sit for long intervals between use and/or very short trips

[@edwarddhondt]

Again a correct comment Joshua, thanks for explaining it more in detail. The ideal temp is perfect for an engine especially when running 24/7. purr's like a kitten as we say

[@ShainAndrews]

Arc gouging is fun. A person can be pretty precise with the process. As for concrete it destroys it just like a torch will. Rapid expansion of voids in the substrate causes it to explode. The voids always have some percentage of water which adds to the expansion and energy.

[@SuperSecretSquirell]

Love me some mini torch. I use them to burn the equalizer bar pins out of dozers if they dont want to cooperate with the 20# sledge. Smokes out a shop in no time so make sure your exhaust fans are on.

[@wesleynyhus8165]

Thanks man I was unsure about oil temp on my 6nz thank you for your expertise

[@SP-mp9yi]

Now that you say this it makes perfect sense, thank you because I never stopped to think too much into the "swap the thermostat" bad advice. So if I'm right that would mean; Larger Radiator for the thermostat to pull from if needed, because "Operating Temperature" is simply that, operating temperature. On classic cars they often have aftermarket oil cooler s available but now I'm wondering about the engineering that's gone into them and do they possibly create a new issue of there own because many are generic kits. LoL "Bolt this on and treble your oil capacity"

[@rustypotatos]

that lancing event is unreal man

[@zxej6879]

At 66 years old, I have been dealing with motor vehicles for 5 years. To have a cooler running engine, pay attention to; air flow, oil viscosity, and belt slippage. Serpentine belts have greatly reduced belt slippage. But applying a little rubber cement on the friction surface of a belt can test belt slippage. Also some engine will run cooler with a slightly smaller or fewer blade fan. With the fan shroud adapted for the diameter. The fan may be creating to high a load on the belt system. When people alter air dams or increase the lift on the front of a vehicle. Overheating can occur. A lighter weight base oil can help heat transfer. And therefore improve cooling. Use 5w40 or 10w30 synthetic, rather than 15w40 or a single grade oil. And maintain the correct oil level. Too high or low a level can cause a variety of problems. Of course all of this assumes a properly operating engine. The radiator is clean for coolant and air flow. The timing and valve adjustment is also correct. And the driver is not lugging the engine!

[@jeeper426]

i've had arguments with the parts counter jockey a few times at the local auto parts store, i installed the OEM spec 195 degree t-stat in a 4.0L jeep engine, the kid behind the counter kept trying to talk me into a 160 degree t-stat because "its what hes done in his jeep and it never overheats", i've tried and tried to explane to him pretty much what you covered in this video, but of course if its not on reddit kids these days dont believe a word of what a mechanic says, thanks for the video, and now i can show some of the nay-sayers and poo-pooers about t-stats that yes it is an important pierce of the cooling system and not a good idea to just throw it in the trash and run without one, though i will admit in the past i did have to make an emergency decision because i had a t-stat fail on me in the closed position, and i had to make a flow restrictor out of the cut up body of the t-stat and a fender washer to limp to the autoparts store to get a replacement one, but it was less than 20 miles, and i ran it for not more than a couple of hours total with that in there, also why i preach FailSafe t-stats are a must, if one is going to fail, i'd rather it fail in a mostly open state as opposed to completely closed where it'll burn everything up faster than being jammed partially open, also thermal lances are pretty sweet, but as you said extremely dangerous to be in close proximity to while in operation

[@comics3437]

This is Mind Blowing

[@Drivehead103]

Is that the same thing as a gouging rod? I discovered gouging rods in the early nineties when I was a diesel mechanic.

[@J.R.in_WV]

A colder thermostat will never fix an overheating issue as long as the stock thermostat is functioning properly. That said in a mechanical engine a cooler thermostat will bring down the standard operating temperature and I found in a big cam Cummins, mechanical cat or mechanical Detroit that a 160 thermostat gives the lowest spikes in coolant temp on long pulls vs a 180 or 190 T-stat. What I mean by “spikes” is, especially in the winter, when you’re pulling a good hill in a loaded truck with a 180 or 190 thermostat the thermostat will often stay shut until you get into a good pull, and due to the design of the coolant bypass and the facts thermostats are not super precise or fast opening the temp will often spike to 210 or more then the thermostat opens fully and it drops rapidly on the gauge as the overheated coolant is allowed to flow in to the still cold regulated side of the radiator at full flow. We’ve found the 160’s will open and stay open as long as temperatures aren’t sub zero or something and the cooling system works better by running at its full flow capacity all the time at temperatures between 15 and 60 degrees F, which is about 2/3 of the year here. Obviously on an electronic engine this is not a good idea as they are able to vary several factors based on temperature inputs that will drastically decrease efficiency if run colder than designed all the time. Depending on the make and model of truck engine the ECU can vary: Injection timing, number of injection events, in some cases fuel pressure and even Governed operating RPM, and of course fuel flow, based on coolant temperature data.

[@ryanc8188]

I could see a 10 degree thermostat temp change but 20+ is to much.

[@jamesolsen9599]

i have a marine gen in a engine compartment with two big blocks running at 180 temp in florida my gen had a 190 temp thermostat engine running at 201 temp i put a 160 temp thermostat in engine runs at 180 182 sometimes 185 explain ?

[@cullenmiller8170]

It's never a good day when you have to bring a thermal lance out to remove parts of a truck. I can't believe that that king pin got so stuck in the grease that you had to melt it out. :-)

[@Graveltrucking]

The new emission engines the hotter the better. If you've got over heating problems look at your radiator, cooling fan. Got the fuel cranked up, hell a plugged air filter can cause an engine to run hot.

[@nobleroofinggeneralcontrac7961]

I have a 7.8l old Ford/ Brazilian engine once it gets to operating temperature it runs smooth.. Takes about 45 minutes to warm up after start at idle with an ambient temp of 50 degrees out.

[@timmay2k]

If your engine is getting hot most likely you either have a clogged radiator or a bad fan clutch. Besides thermostats are there for a reason. Once a certain pressure the engine gets it opens up the thermostats to push coolant into the block. Remove them you have too much back pressure then kaboom.

[@rustypotatos]

what about a lower temp engine coolant fan sensor so the fans come on earilier?

[@MrSodium271]

My car which is a Peugeot 206 (made 4 years ago in Asia) has been running cold for a month, Im gonna replace the faulty thermostat tommorow, When running inner city it was alright but on highway it went down to 60 Celsius (140-50 F). How much of a damage I should expect in the engine? I drove average of 20 mins per day (in highway) - never had any overheating problem, normal temps in the city.

[@clydejabines7186]

Good day sir in cat c15 does have a oil thermostat and what is the main purpose? Tnk you

[@vivillager]

Got a question. I recently replaced the radiator, water pump, and thermostat, and radiator hoses. Nothing wrong with the ones I removed, wasn't overheating, they were just old and I wanted new ones. When I replaced my thermostat, I had the bright idea of drilling two 1/4" holes in the thermostat to aid in "burping" the cooling system, or purging the air out. Now my engine takes longer to get up to temperature. Also, my engine runs about 10 degrees cooler if I let it idle. It comes up to normal temp when I'm going down the highway, especially with load. Something for me to worry about?

[@606budwheel]

only in the winter, wear heavy socks!

[@fake2822]

That won't cause any issues, save for the ones you're having. The holes you drilled are way too big. Usually one 1/8" hole is plenty for air bleeding. Many new thermostats even come with a bleeder valve installed, maybe you can find one for your vehicle

[@user-uj3zk2cx8t]

You drilled the holes too big, but it shouldn't be anything to lose sleep over.

[@davidchappell1548]

If basically everything (and I mean EVERYTHING... even has a heavyhaul radiator) has been check/replaced on a BXS ACERT C15, what would you recommend checking? At ambient temperatures over 70°, it overheats. The hotter the ambient, the more gears I have to drop to keep it below 225.

[@johnnybigmack1332]

Must be 🌞 and warm in josh world this time of year.😁😁

[@AdeptApe]

The next video I'm posting, it's in the snow, but I had some sun before this one.

[@Gordonseries385]

Can a type of oil be used instead of antifreeze?

[@dennissmith460]

Tigertool makes a king pin press that is well worth the price. Especially if you do that for a living. Bought one to do the king pins on my lift axles, and have never regretted it. I'd say it's it's a much better option then that hot mess there. Lol

[@matsinkal]

what if you have a turbo barra with a tune and more boost though

[@BIGGIRL0214]

Hey I hope you can help me I have a maxxforce n 13 😢 but i replaced heater core hose and now it won't high idle or keep coolant temp up at idle it stays 110 140ish . Running down the road it will run 184 and 200 on hills didn't do this before. I left reservoir cap off and ran it to burp ..no luck

[@roochibon1]

What!!! An Engine is not a person?!! Im flabbergasted..lol Thanks for the info. Helpful👍

[@victorgirouard1543]

A king pin press and some heat works wonders!

[@adrianspence1055]

What is the normal water temperature for the C12 Cat engine

[@bryanknox5014]

Have a 99 kw c15 can't get the fan to kik on is there supposed to be power at the heat sensor working with ac one hand switch

[@MrNofruitjuice]

Dude check out air arcing if you never have seen it before. It's great for large jobs of metal removal and welds

[@Coyner4321]

If you ever get a newer Pete glider kit in the shop with a Cat motor, could you make a video showing where the oil temp sensor plug is on the harness please? My glider has a oil temp gauge but the original builders didn't hook it up and I have absolutely no idea where the connector is hiding in the harness.. I really want the gauge to work, that one and the trans temp gauge are the only two that don't work on my dash (also no idea where that connector is hiding).

[@johncholmes643]

I hope everything Facebook Caterpillar engine expert watches this. I have talked so many customers off the edge of putting cooler regulators in in their engine's. I tell them basically what you said in a reader's digest version.

[@fastinradfordable]

I had a customer come in with a cold air I take that let water in the engine. I showed him the scotty Kilmer video about it. The look on his face.. made my day

[@selbalta873]

Hi Josh I changed me thermostats but didn’t change the lip seals would this affect any thing?

[@Greg-w6t]

Thank you for the info. I learned so much from your video

[@heaveymelt]

That Lance is cool never seen that before thanks for sharing

[@scotthewins5341]

C12. Engine fan kicks on at 206°. Is this normal? 04 T800. Thanks

[@DavidSmith-ff2vl]

I saw your video a couple months ago regarding installing a wiring harness on a Cat engine. I'm trying to find the loom Cat uses on their wiring harnesses that protects the wires. I've asked local Cat parts guys and every time I do they say I can't get it and act like I asked for some trade secret and quickly change the subject. Is it proprietary or is there a supplier I can get it from? Thanks for you input. Love your channel!

[@Mopar.Country]

What are your thoughts on Lucas Oil Products? Such as their oil stabilizer.

[@Sens23Bruins]

Lances are pretty cool but a kingp8n press works too

[@truckintomg]

Love your videos Josh keep it up!!

[@mikekahl5609]

I have a question about DEF and sensors. My township road crew wants to replace our old but low hour road grader with a brand new $330,000 Cat grader. It is parked in a shed 11 mounts out of a year, so would the emission parts fail easily setting that much? Thanks.

[@cwj9202]

What is the reason for the grader needing replacement, and what is the old grader (120G or something newer)?

[@mikekahl5609]

@@cwj9202 one person just wants to replace the 30 year old machine and keep on a schedule of replacing all equipment averaging $100,000 a year so it is in the municipal budget.

[@cbmech2563]

@@mikekahl5609 ahh, the old "if the money is in the budget we have to spend it so they will give it to us in the next budget". Typical 😥

[@cwj9202]

@@mikekahl5609 -- Having worked for a government entity, I will say I have heard that questionable rationale before, "It's in the budget!" A grand waste of taxpayers' money! We had nicely functioning heavy equipment whose age exceeded 50 years and hours that were low. That $330,000 would look nicer on the roads and in any existing potholes.

[@mikekahl5609]

@@cwj9202 That's exactly his reasoning, its not my money and I want new equipment.

[@timothy4037]

What is the recommended thermostat for a 6nz? I recently bought a 03 kenworth with a 6nz with 768,xxx miles. It stays at 155 but here in texas it 100* so the temp goes up to 175. Thanks for your amazing videos

[@JohnnyAGraves]

I’m running a C-15 ACERT. when idling at night, what’s the best RPM should I have the engine?