I want to get the 85 degree thermostat... is this the pathway?

[Timm]

The DME alters the injector dwell against lots of factors including the coolant temperature, so having a lower engine temperature is just normal operation!

[nmlss2006]

Piotr, I am on record on the forums and as far back as Welty's mailing list in the 90s as bitching about several of BMW's engineering choices.

So no, I don't think everything is perfect. As a matter of fact, even if you limit yourself to this particular subforum you'll find plenty of posts where I have complained often and loudly about many things in the E38 which could have been done differently.

However, I do think that absent a significant amount of hard data I will not change one of the engine's primary operation parameters in order to be able to change coolant hoses every fifteen years instead of every ten.

While I appreciate that our understanding of materials has improved in the last eighteen years, I will take BMW's opinion on this matter unless I have something equally authoritative to contradict it. And as racer2086 has pointed out, nobody does.

But of course, to each their own: I'll replace hoses and radiator every ten years, including the fan clutch, and keep driving. Others can do as they please, as long as they don't claim to do it with full understanding of what is going on and why.

[racer2086]

I just wanted to post back here, because I had recommended that "recalibrated" thermostat as having worked well in my car.

Well, today I decided to check again and see how things were doing by unlocking by cluster to test 7. I was shocked to see my temps fluctuating between 105-107. They used to be lower. A/C was on, but ambient temp was only 76. Not right.

So I emailed the guy back to see what he says about that, since I paid him $50 to recalibrate a new OEM thermostat to...an OEM thermostat.

Don't know how I got away with having my radiator cap totally loose. I will post back with updates as I get them.

Lewvrig, since you have the same stat, what does your car run at? Can you check test #7? Want to know if I just got unlucky or what. Thanks

Edit: Immediate response from Logic7. I'm going to try to swap out thermostats, but need to figure out how without leaving my car down. Will update when things progress.

[cyclops2]

Well I ordered the wrong parts (thermostat and housing), wrong for my car anyway. Mine is 5/96 build E38 M62 with clamp on hoses. stock 105C stat: Goal is 85C stat

My OEM 105 C thermostat is on the left. I thought I could order individual 85 C stat and housing (about $40 for both), but apparently not. The individual parts; housing and stat (85C) won't fit the waterpump on the M62 without modification.

20180323_070209.jpg

Attachment 625295


Turns out, I need a single unit/assy design, same as the 105C stat. Individual parts won't work without machining and/or fabrication.

So knowing that I starting searching for the best deal/source. They are not common and hard to find actually. In fact, I couldn't find one in stock.

I ended up finding the best price at Morristown PA BMW @ http://www.bmw-oem-parts.com for the 85C unit for M62 with clamp on hoses (not the M62TU needs the unit where the hose clips on) anyway they have them priced at $105 shipped. part number: 11-53-1-742-964 Here is a pic I grabbed off the Internet:





Problem is there are none; they had none and he checked nationwide inventory and there wasn't any. He called BMW and was informed that they are manufacturing them (vendor is) and their is no inventory at dealers in US or Europe...WOW. So wait time is unknown, probably at least a month. I had him go ahead and order one. I really wanted the 85C stat. and what's a month in a 5 year project.. haha.. I have a lot of things to do and if I get them all done, I can install the 105C stat temporarily.

[cyclops2]

Not great pics but I also purchased the 1.4 bar expansion tank cap. Dimension same as stock 2.0 bar cap.



20180323_002549.jpg 20180323_002645.jpg

[cyclops2]

IF YOU WANT A SMOKING PRICE ON A 85C Thermostat and don't mind a risky purchase on a sketchy website.

HOW ABOUT $45 .. shipped! Says BMW branded.

Check it out. more than half the price... I was so close to trying, I put it in my cart... and then chickened out...lol

https://www.elitmalls.xyz/thermostat...64-p-10989.htm

[lewvirg]

the tstat I bought was inclusive of the housing for both cars. When I read the word recalibrate - I assumed that since the dme controls temp by heating the wax bulb- that they lowered the operating temp by increasing the length of the piston/or shimmed it? Sounds like either the wax capsule is screwed or the disc?

I usually run either 7 or 9 while driving, mostly with ktemp. On a very hot day in the central valley (about 100 to 105) at idle at a light - the temp was at 100 with a/c. Once moving it went down to 96/97. Usually on the coast where it is in the 60's the temp at idle is 98.

[DorinDav]

To each their own...and mind your own

Also, where do you get the 15 years vs 10 years info? It fits your narrative while being patently false.

[PiotrC70]

For you guys that have the 85* stat and still seeing temps from 100-110 makes me think you have air in the system. I'd be curious on unplugging the MAP connector (temporarily) and seeing what your true ktemp are without the DME interfering. I have the 88C in my M62TU (no MAP connector) and my average temps are about 92-94 and on cooler days say <50F on the freeway have seen as low as 90C. The true test came when I was up in the mountains last year and it was 99F outside. I had the A/C on, in stop & go for a few miles, and only then did my temps hit about 102. Once I got moving into freeway speeds, temps dipped back down to about 95C.

[DorinDav]

I use 88° in South Florida
Idle at 95° and 99° on hard driving
All cooling system components are newish save for rad
I splurged $30 on 1.2 bar aluminum exp tank cap

I do not use fan and clutch, opting for spal electric

Mileage has suffered ...I lost 1.2 MPG which raised my fuel costs about 6.5%

[purplecty]

A friend of mine installed an additional trans cooler in his 4.6is x5, which runs the trans at 80c and he said it also makes the engine runs around the same temps... He said he may have gotten an error 2x in below 0 degree weather for trans temps too low but otherwise said it runs great and give piece of mine with the cooler temps...

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[georgebest]

There's no problem running an 85C thermostat - the E31 840ci has an 85C thermostat as standard when using the M62B44 engine in some country variants:

http://www.realoem.com/bmw/enUS/show...diagId=11_4950

.....and has a 95C thermostat everywhere else

That kind of settles the argument, same engine coming from BMW with 85C, shouldnt be bad for the engine.

[purplecty]

Its not this one?

https://www.ecstuning.com/b-vemo-par...512248542~vmo/

This one says 88 degress but its for the M62tu...

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[purplecty]

Lower operating temp & electric fan are tried and true

Cheers

- - - Updated - - -

There is a 1.2 bar expansion tank cap on the market

Expensive though at $35

Where can you get this? Will this be a good match with the 88c tstat?

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I ordered one of these for my M62TU...

https://www.amazon.co.uk/gp/aw/d/B00...?ie=UTF8&psc=1

[cyclops2]

Where can you get this? Will this be a good match with the 88c tstat?

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I ordered one of these for my M62TU...

https://www.amazon.co.uk/gp/aw/d/B00...?ie=UTF8&psc=1

Here is the 1.2 bar cap. it's a beaut at $35. http://www.germanautosolutions.com/p...hp?product=145


or you can go this route, which I did, with a 1.4 bar OEM (no BMW logo) Behr cap for $10.50:

https://www.autohausaz.com/pn/17111719167


I have read where people are using either. These cannot be used unless the pressure has been lowered by lowering the temperature or using something like Evans waterless coolant.

General reminder: A lower bar cap doesn't lower the operating pressure, just lowers the emergency safety vent/blow-off pressure so that coolant pressure would blow at 1.2 bar rather than 2.0 bar as factory designed for our vehicles.

[PiotrC70]

Thanks Cyclops, will likely pick one up. 99% of my coolant system is refreshed with all new hoses, valley pan, etc... the only original thing still is the radiator & expansion tank. Since I'm already running a 88C stat, this should pair nicely with the lower pressures I'm already running.

[purplecty]

Here is the 1.2 bar cap. it's a beaut at $35. http://www.germanautosolutions.com/p...hp?product=145


or you can go this route, which I did, with a 1.4 bar OEM (no BMW logo) Behr cap for $10.50:

https://www.autohausaz.com/pn/17111719167


I have read where people are using either. These cannot be used unless the pressure has been lowered by lowering the temperature or using something like Evans waterless coolant.

General reminder: A lower bar cap doesn't lower the operating pressure, just lowers the emergency safety vent/blow-off pressure so that coolant pressure would blow at 1.2 bar rather than 2.0 bar as factory designed for our vehicles.

So I'd only want to go this route using the 88c tstat?

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[racer2086]

Yes, or some lower temp stat. The higher running temps of 108-110 from factory require a high pressure in the system to prevent boiling.

[oldroller]

There will be no issue with running the original 2.0 bar cap with a lower temp thermostat.
If for some reason the temp gets up, it will prolong a 'release' until the pressures get up to the high 20's psi.
Hopefully you will be eyeing the gauge well before then....

[purplecty]

There will be no issue with running the original 2.0 bar cap with a lower temp thermostat.
If for some reason the temp gets up, it will prolong a 'release' until the pressures get up to the high 20's psi.
Hopefully you will be eyeing the gauge well before then....

I drive with the cluster unlocked. It's a must for me...

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[cyclops2]

oldroller,

I understand and agree with you. I just like the idea of knowing that my system will blow at 1.4 instead of 2. I may go to the 1.2 bar cap, pricey, but a piece of art.

In my other post, I think I have dialed in my coolant "mix".

I look forward to getting the car back together with the improvements and see how it does.

.............heck at my pace, there may be a new technology I'll have consider on this topic! lol

and the 5 year build keeps on chugging along...



and purple, I have been thinking about a heads up device or something like a scan gauge to monitor various outputs via the OBDII port while driving. both are cheap these days.

[nmlss2006]

Dorin, it really isn't false. I will ask, again, how many people were running around replacing entire cooling systems in E38s before 2005. The answer is 'not very many'.

But, with the further information - which I was not aware of - that the stock cap has a 2 bar pressure cap, the entire pressure theory loses any of the theoretical credibility it had. For reference, by the by, water boils at 109C at less than 1.4 bar. There are other factors involved but the fact remains that the net effect is, to put it midly, very small.

So you are correct in a way: I severely overstated the possible benefits, thus making the entire exercise even more useless. Reducing the pressure from 1.4-1.6 bar to 1.2-1.4 bar (yes, the pressure will remain positive ... the only systems where it will not in recent engines are marine engines which run at or around 80C for several reasons, none of them to be honest very good) will not actually change much in the life of the rubber or the plastic. Will the temperature make a difference? If we're talking 105C vs 95C, the answer is once again, not really. You will not extend the lifetime of the components by 50%. Will you extend it some? It's possible, but TBH I am willing to bet that most of the failures did not occur with OE parts. How do I know? See above ref. the years when the cars were new.

I hope this spells things out clearly enough. I'm afraid I was not just spewing off, so 'to each their own' needs a qualifier or two.

Which would be fine, if in this thread like in the other your primary problem were not with me while people are changing things in ways which are at best not proven or negligible if not outright pejorative of the status quo.

That really is not fine. But I'm done arguing, because there is no value in it. I am sure plenty of other people can provide content.

[DorinDav]

Dorin, it really isn't false. I will ask, again, how many people were running around replacing entire cooling systems in E38s before 2005. The answer is 'not very many'

I agree with you 100%

Here's some anecdotal:

I love running my 100k mile M62 at a consistent 96° instead of the range of 99°-114° with the electromechanical thermostat

I love not having a fan & clutch

I also love coilovers and fat tires

This car is my toy & I set it up my way and it really is gobs of fun