Lowering the opening temperature of the n62 E65 BMW thermostat

The opening temperature of the N62 thermostat is set to 105 degrees centigrade. This is a hot temperature setting and its known to contribute to coolant leaks and coolant tank failure. Lowering the temp is a good method to increase the life expectancy of the cooling system. Lowering the thermostat to 95C or even 90C is recommended for this car.

[@jp3630]

Thanks for this video. Considering hi-temps and long service intervals are the reason for N62/engine failures, you would think they'd be a lot more videos solving this.

[@michaelatwal3007]

Amazing video!! Been reading up as my 645ci N62 is running cold...max 80 degrees in the secret menu...and now after your video I understand how to check and how it works - and I was scared to buy a new one as don't want the car hot running! Absolutely perfect video look forward to the next!

[@marktolner2922]

Thank you so much for this amazing video. I have just purchased a fairly expensive generic 90 degree thermostat from the USA and am fitting it today. As you demonstrated the cheap ones do not seem to be much different to the OEM one. My car is an E66 760 (V12) and I am obsessed about dropping its operating temperature to avoid putting pressure on all the new hoses and other cooling system parts that I recently replaced. At 107 to 110 degrees these engines are a ticking time bomb waiting to let you down and raid your wallet. By the way, I use a paper drip coffee filter in a funnel to clean any fluid that I reuse. People laugh when they see a pack of coffee filters in my tool chest. Your amazingly detailed and practical videos are a "go to" source of information for me along with George Auster and SATS Motors and Vehicular DIY videos on the 760Li and E65/66 cars. Thanks as ever - Mark. PS - if my expensive generic from Turner Motorsport that I am fitting today is no good then I will try your wax trick using wax from the original thermostat which I thankfully held on to and can use a doner.

[@marktolner2922]

Well I fitted the Turner Motorsport 90 degree thermostat and it seems to open at about 97 degrees rather than 90 degrees. Anyway it has reduced the cars maximum temperature reached 97 to 100 degrees rather than the 107 to 110 degrees it used to hit with the BMW standard 105 degree thermostat, so that is a meaningful improvement and I will probably leave it there for now. The low point is about the same as before at around 90 degrees. Readings are from a cheap generic scan tool in the OBD port and displayed on my phone through an all. Hopefully those are the same as would be indicated in the "hidden menu" on the dash. Anyway, thanks again for your video - I will keep your method up my sleeve for now.

[@ecologicaltime]

thanks for watching and the great coffee filter tip!

[@ecologicaltime]

glad it offered some improvement. I was also going to get the Turner option but i needed one urgently and Amazon was faster shipping all the way to South Africa. Its seems that the Turner would have saved me a lot of time... Ill try reading the temp from the OBD port

[@KhanNakash]

Great video, appreciate your dedication to this car! I have a 2003 745Li and all these videos help a lot! Would love to see one on a dynamic drive leak fix, I currently cant use my car because the o ring in the unit is leaking so much there isnt enough liquid to keep it driving.

[@ecologicaltime]

thank you. I also have that problem but its not at the stage yours is.

[@arthipc1613]

waw..so amazing

[@_J.P._]

5:54 mmmm... voltage and current sauce, my favourite as well :D

[@e60_545i]

Mine is stuck open and I’ve already replaced it and I was wondering what if I put jb weld over that small circle would that help it close ???!

[@cltrovers]

I'm interested in a similar modification but with a different thermostat. The one I'm working with disassembles so I can easily replace the spring. Would a weaker spring encourage the thermostat to open sooner. Currently it is a 88 degree and would like for it to be 82 degree.

[@paperandmedals8316]

Curious if MAP can be programmed to open the thermostat sooner? I have a M62 in an E38 in very hot Phoenix Arizona USA. The OE thermostat is also 105C.

[@amiraux7234]

How does the fan operate?

[@sonnys7032]

If you heat up neodymium magnets they won’t be magnetic anymore . Try it .

[@levantsulaia3804]

My car is a 528xi and it has this thermostat here. When driving, the temperature drops to 76-80 degrees and the engine runs cold, is there any way to increase the temperature a little?

[@sgtmaj2]

Did you ever try this same experiment using coolant instead of water so you could get the proper temperature while adjusting the wax content?

[@ecologicaltime]

yes, it didnt go well. Could not get the temp in the pot to go high enough

[@tiago_BMW]

Very interested for this mod, can you make one and sell it to me ? :)

[@BBOYMixFive]

I made a "cooler" thermostat but i've got an error about mechanick part of thermostat. But it works as must be and open about 90-92. But i've got a "check engine" symbol and it's making me sad...

[@marktolner2922]

Perhaps you damaged the electrical heating element inside it in some way when you were working on the thermostat and it is now open circuit or you did not reconnect cable fully? Good luck!

[@BBOYMixFive]

​@@marktolner2922 i had checked this element via multimeter (checked both of wires) - it has no open circuit, because i heard a multimeter's ring. This is the right way of check?

[@marktolner2922]

@@BBOYMixFive Sorry Mike but I am not an expert. What I could add is that whilst it is true that your element is not open circuit it may break down when a current is applied and would therefore not heat up? I wish I had a machine like ecologicaltime's that would allow such a test I think.

[@ecologicaltime]

i had an e65 that was running at about 65C for over a year and i never got check engine light however on INPA is does show a fault code for thermostat. Have you scanned with INPA?

[@ecologicaltime]

the ringing means the ohms are low which is correct but it could also mean a short circuit. Please measure the resistance between the terminals. I did a video on the mapped function and i think it was with that same thermostat and it has the resistance value for it: kzbin.info/www/bejne/aKLCqX9ohZZjars

[@zekedawgg1986]

You must live on mount everest if your water boils at 163 degrees F

[@nzwakele]

Just do a thermostat delete

[@ecologicaltime]

whats that?

[@nzwakele]

Don't put a thermostat in. Granted the car will run longer on a lower temperature but it's better because yu won't overheat

[@ecologicaltime]

The wear and tear on slow warm up would be catestrophic. Most parts designed for 90 degrees. The thermostat also works according to a map function. I have a video explaining map functions

[@summushieremiasclarkson4700]

Absolutely terrible idea, please nobody do this. Running slightly too hot (as BMW designed it) will trash your gaskets, fixable PITA. Running too cold for too long will trash your entire engine, and pretty quickly too. Unifxable.