Modifying M62tu thermostat

[Mannyf540]

Found this doing some research, whoever ( Jim ) could make one if these, I think would be quite cool.Essentially you can modify the thermostat to open before the 105, or whatever the factor setting is.


http://www.xoutpost.com/bmw-sav-foru...long-post.html

[JimLev]

I saw that about 18 months ago, printed it and was going to do it. I have almost all of the parts needed.
Just never got to it.

Then a few months ago someone was posting about cutting his coil springs to lower the car. We told him it wouldn't work.
He then said he was going to heat them. So thinking outside the box I thought this t-stat would be even easier.
I'm ready to get flamed for this red neck mod.....bring it on.

I took one of my 3 spare t-stats and heated the spring to reduce it's tension. There is no way to determine what your going to end up with.
After I was done, all of 45 seconds, I put it in a pan of water with a Fluke digital thermometer.
At 98.5°C it started to open. Not bad, got it on the first attempt.
I now need to put it in my car and see what it's operating temp will be.

[philly98540]

I'm liking this already. Very clever. Sub'd.

Report operating temps when you get a chance to install it.

[supra94tt]

I did my research too and ended up with a European diesel 4.4 thermostat rated at 88C. Driving around I see temps in 90-93C mostly due to stock fan clutch which is rated at 93C, if I could install a fan clutch rated at 85C maybe I could see temps around 90C, but so far I'm happy with the mod.

[Mannyf540]

I saw that about 18 months ago, printed it and was going to do it. I have almost all of the parts needed. Just never got to it. Then a few months ago someone was posting about cutting his coil springs to lower the car. We told him it wouldn't work. He then said he was going to heat them. So thinking outside the box I thought this t-stat would be even easier. I'm ready to get flamed for this red neck mod.....bring it on. I took one of my 3 spare t-stats and heated the spring to reduce it's tension. There is no way to determine what your going to end up with. After I was done, all of 45 seconds, I put it in a pan of water with a Fluke digital thermometer. At 98.5°C it started to open. Not bad, got it on the first attempt. I now need to put it in my car and see what it's operating temp will be.

Actually Jim that's quite cleaver !!! Please keep us posted on this mod, I have a torch and ready to heat the spring, so you heated it for 45 seconds.

[BimmerBreaker]

Just chiming here... engines operate most efficiently within a certain temperature range. Running lower temps is not always inherently better.

A car with a broken thermostat runs cooler and gets worse mpg and worse performance then a car at correct operating range. Dropping a few degrees is no problem, 95C is about the lowest I would want to go.

[Mannyf540]

Agreed their BX, if Jim could find the optimal heating time to get that magical number it would be great !!

[JimLev]

Actually Jim that's quite cleaver !!! Please keep us posted on this mod, I have a torch and ready to heat the spring, so you heated it for 45 seconds.

It might have been even less, that time was for both sides. I did this about 3+ weeks ago.
As soon as I saw the spring starting to glow I stopped and did the other side.
You need to use a pencil tip flame torch to only hear up the spring and nothing else. Hold the torch parallel to the spring.

I didn't want to lower the temp too much, same reason as blackxs stated.
I hope to test it out soon, will post results.

[Mannyf540]

I did my research too and ended up with a European diesel 4.4 thermostat rated at 88C. Driving around I see temps in 90-93C mostly due to stock fan clutch which is rated at 93C, if I could install a fan clutch rated at 85C maybe I could see temps around 90C, but so far I'm happy with the mod.

Got a part number or link for this thermostat ? How's it working for you ? Direct bolt on, or did you have to modify anything.

[philly98540]

I did my research too and ended up with a European diesel 4.4 thermostat rated at 88C. Driving around I see temps in 90-93C mostly due to stock fan clutch which is rated at 93C, if I could install a fan clutch rated at 85C maybe I could see temps around 90C, but so far I'm happy with the mod.

I wonder if they have a similar 88C stat that is a direct fit on my pre TU?

The one you have is for the newer clip on hoses.

[BimmerBreaker]

Got a part number or link for this thermostat ? How's it working for you ? Direct bolt on, or did you have to modify anything.

88C is too cold IMHO

Jim, any input on that?

[supra94tt]

Just chiming here... engines operate most efficiently within a certain temperature range. Running lower temps is not always inherently better.

A car with a broken thermostat runs cooler and gets worse mpg and worse performance then a car at correct operating range. Dropping a few degrees is no problem, 95C is about the lowest I would want to go.

It depends on what you mean by "lower" temps. 14.7 a/f at 80C or 95C is still 14.7. Would you see monumental losses in MPG due to temp/friction difference, very miniscule, if at all. E39 M5's run 77C thermostat running about the same MPG as 540's on highway.

[JimLev]

88C is too cold IMHO

Jim, any input on that?

20 deg lower is a lot. I did have a stuck t-stat years ago, it would take forever to get up to 90C. I did notice it took a lot longer for the engine to warm up and to heat up the cabin.
Never checked the MPG.

[BimmerBreaker]

Does seem like a significant drop to me as well...

I dont want to start an argument here, but I do urge anyone considering dropping such a significant amount in their thermostat to do a lot of research on the topic first

[supra94tt]

Stuck open is different than normally opening thermostat, my car warms up as fast as with the stock thermostat, I just dont cook my engine and timing guides anymore .

- - - Updated - - -

Got a part number or link for this thermostat ? How's it working for you ? Direct bolt on, or did you have to modify anything.

Direct bolt on, no more connector though, but no check engine light. Post # 8 http://forums.bimmerforums.com/forum...-it-works-well

[geargrinder]

I looked into the diesel thing - it comes in several flavors (temps) IIRC but real hard to find here. Id like a slight temp nudged down stat but agree w the fact that low temps are not better temps for both performance and efficiency. If i could find the diesel model in 95C say i might try that if i could find a source to ship to USA#1....

[BimmerBreaker]

If i could find the diesel model in 95C say i might try that if i could find a source to ship to USA#1....

Im quite sure this thread is about a way to modify your thermostat to open at 95, or wherever you want

95C seems to be where its at

[tasjackal]

On the topic, my 1998 540i pre-vanos runs constantly at around 80c... if I am parked and idling it will eventually get to 104c where the aux fan kicks in and brings it back down to 80-90c. I did a mechanical fan delete and it is winter here (under 10c) but still I think its running too cool for a 540i.

[Alpina540i]

I also use the 88 C direct fit M62tu thermostat and my operating temps are between 93-95 C cruising and 99 C A/C on idling.

No mechanical fan either.

[AK_5eries]

I wonder if they have a similar 88C stat that is a direct fit on my pre TU?

The one you have is for the newer clip on hoses.

There is one rated for 95C. That is what I am going to use when my current one pudondadonks out.

- - - Updated - - -

Interesting tid bit: E39 M5 runs on 79C thermo.

[whiteghost1]

I also use the 88 C direct fit M62tu thermostat and my operating temps are between 93-95 C cruising and 99 C A/C on idling.

No mechanical fan either.

I have the exact same results with the exact same setup. It's the perfect balance for all operating parameters in my book......

[geargrinder]

Im quite sure this thread is about a way to modify your thermostat to open at 95, or wherever you want

95C seems to be where its at

I know, I'm sayin' I'd like to find the diesel version that's PNP for TU's instead of doin the spring heat mod which I'm not sure I'd trust 1000% for long term.

[supra94tt]

I know, I'm sayin' I'd like to find the diesel version that's PNP for TU's instead of doin the spring heat mod which I'm not sure I'd trust 1000% for long term.

11512248542 direct fit for M62TU, cheapest place I found, and I think many from this forum bought it from: http://www.estore-central.com/part/11512248542, please email the guy first and he may give you even a better deal. My total shipped to the states was $150.

[Mannyf540]

Here's a thought, perhaps the newer DME's will trigger a fault, perhaps they've been remapped. I assume this because it seems the older models seem not to get a fault triggered or a check engine light.

Also anyone the has put a resistor to satisfy the DME, any pics or a DIY ? I'd like to put a resistor, my DME is a 7.2.

[Flounderasu]

Here's a thought, perhaps the newer DME's will trigger a fault, perhaps they've been remapped. I assume this because it seems the older models seem not to get a fault triggered or a check engine light.

Also anyone the has put a resistor to satisfy the DME, any pics or a DIY ? I'd like to put a resistor, my DME is a 7.2.

Click through Supra's link. It's all in that thread or linked in that thread.