X5M s63 Cold 90C Thermostat

[Leon S. Kennedy]

Guys, I've just serviced my S63 and almost changed everything on it. It was most expensive service in my cars. So, I started finding solutions how to reduce heat in my s63 because we know that this 105C working temp. kills all this seals, rubber and etc.

I was thinking to buy HT 90C thermostat from ECS but done research about this cold thermostats and find out that this 90C thermostats mechanically tries to open after 90C. Thats why it runs from 90C to almost 100C just unstable. Our thermostats are map controlled by car ECU. Because of that car is unstable under this cold therm. ECU tries to reach its working temps when 90C mechanical thermostat opens thats why we will have rich mixture and errors in ECU.

Also I find out that its possible to program ECU and it will open therm. on 90 or 95.

So what do you think about this cold thermostats?

P.S. I monitored my car and it always runs 105C to 108C

[Sophisticated Redneck]

Originally Posted by Leon S. Kennedy

Guys, I've just serviced my S63 and almost changed everything on it. It was most expensive service in my cars. So, I started finding solutions how to reduce heat in my s63 because we know that this 105C working temp. kills all this seals, rubber and etc.

I was thinking to buy HT 90C thermostat from ECS but done research about this cold thermostats and find out that this 90C thermostats mechanically tries to open after 90C. Thats why it runs from 90C to almost 100C just unstable. Our thermostats are map controlled by car ECU. Because of that car is unstable under this cold therm. ECU tries to reach its working temps when 90C mechanical thermostat opens thats why we will have rich mixture and errors in ECU.

Also I find out that its possible to program ECU and it will open therm. on 90 or 95.

So what do you think about this cold thermostats?

P.S. I monitored my car and it always runs 105C to 108C

I have about 10,000 miles on it now since I installed it, it does make a difference dropped temps from avg of 225-230 to 200-210. As you noticed the thermostat has a MAP override that will kick in that little heater in the thermostat and open it even more and when in sport mode it will drop it further and be around 190-195ish if I'm flogging it. Overall I think it's worth it. 225+ is just to damn hot and is why these engines ruin their seals so early.

[zoom750]

Which thermostat is preferred? N63intake.com? Or the Bremmen, Hamburg-Technic from ECS?

[Dawgz]

So....this is something that can be tuned in the ecu?

[Leon S. Kennedy]

Originally Posted by zoom750

Which thermostat is preferred? N63intake.com? Or the Bremmen, Hamburg-Technic from ECS?

I've no idea, N63intake.com has nothing in description to rely on, it just says 84C thermostat. And my mechanic says that below 90C car ECU sees that engine runs cold and makes too rich mixture to rise temp. to normal operating temps. Imagine what happens in car's ECU

about HT thermostat from ECS you can find reviews on youtube where it goes from 93C to 100C and even more in some cases.

Also you can easily find the main solutions on youtube how people make this "cold thermostat"

in case all this thermostats are some kind of fake and just working mechanically. ECU always sees that temp is below normal and tries to warm it up. Because thermostat is electronically controlled by ECU

[Leon S. Kennedy]

Originally Posted by Dawgz

So....this is something that can be tuned in the ecu?

Yes, thats the main thing that our thermostats are map controlled and ECU can be tuned in different heat ranges

I've found out that cars produced for Republic of South Africa has set in ECU to open on 95C and its set by BMW.

So, is there anyone who can tune our ECU's and find that map which controls thermostat to set desired values or is there somebody who can flash RSA program in S63 ECU?

This is right way to naturally lower our engine's temps

[Dawgz]

Originally Posted by Leon S. Kennedy

Yes, thats the main thing that our thermostats are map controlled and ECU can be tuned in different heat ranges

I've found out that cars produced for Republic of South Africa has set in ECU to open on 95C and its set by BMW.

So, is there anyone who can tune our ECU's and find that map which controls thermostat to set desired values or is there somebody who can flash RSA program in S63 ECU?

This is right way to naturally lower our engine's temps

I'm getting a retune for my larger turbos and I'll ask my tuner about this.

[RichardH]

Originally Posted by Leon S. Kennedy

Yes, thats the main thing that our thermostats are map controlled and ECU can be tuned in different heat ranges

I've found out that cars produced for Republic of South Africa has set in ECU to open on 95C and its set by BMW.

So, is there anyone who can tune our ECU's and find that map which controls thermostat to set desired values or is there somebody who can flash RSA program in S63 ECU?

This is right way to naturally lower our engine's temps

I am from South Africa and can confirm that this is not true. But yes it can be lowered with tuning.

[Leon S. Kennedy]

Originally Posted by RichardH

I am from South Africa and can confirm that this is not true. But yes it can be lowered with tuning.

Ok, very good now we know that only tune of ECU can open thermostat on 90C

So, what tune we need or who can tune that?

[Leon S. Kennedy]

Originally Posted by Dawgz

I'm getting a retune for my larger turbos and I'll ask my tuner about this.

Will be interesting what can they advise

[bmwpower603]

Get a turbo blanket. This is scientifically proved to improve performance, and control the damage cause from heat.

BMW engineered this coolant t stat, and oil t stat for a reason. And I can guarantee they have performed more testing than any of these manufacturers selling lower temp t stats.

Only use Genuine parts on a vehicle like this. Unless your planning to track your x5 M, and have it professionally tuned by Nick Pavloski I would stick to what the manufacturer specifications. (Dinan is the only trusted company for aftermarket parts, and engine mapping.)

[Sophisticated Redneck]

Originally Posted by bmwpower603

Get a turbo blanket. This is scientifically proved to improve performance, and control the damage cause from heat.

BMW engineered this coolant t stat, and oil t stat for a reason. And I can guarantee they have performed more testing than any of these manufacturers selling lower temp t stats.

Only use Genuine parts on a vehicle like this. Unless your planning to track your x5 M, and have it professionally tuned by Nick Pavloski I would stick to what the manufacturer specifications. (Dinan is the only trusted company for aftermarket parts, and engine mapping.)

BMW Engineered this Tstat for emissions compliance, not performance or engine longevity. It is why they have the DME override on it to drop the temps when you step on it, then return to its normal crappy high temps during normal driving. Lowering engine temps will increase performance and engine life. Not to mention increase the life of all of the seals in this engine...Same valve guide seals that wear out due to high temps BMW lost millions in repairs on the N63 are also used in the S63 btw...

Anything BMW recommends has been filtered by Government Compliance, Management and Marketing. It is NOT direct from the engineers. Some of it is good, some of it is ABSOLUTE BS. Check on BMW's recommendation on oil changes for the 8 speed vs what the actual manufacture of the transmission recommends if you want just one example.

BMW engineers are brilliant, their management and marketing that have the final say....not so much.

[Sophisticated Redneck]

Originally Posted by zoom750

Which thermostat is preferred? N63intake.com? Or the Bremmen, Hamburg-Technic from ECS?

Cant speak for the N63intake, I have the Hamburg unit from ECS. Some bad reviews out there but haven't had any issues with it.

[Sophisticated Redneck]

Originally Posted by Leon S. Kennedy

Yes, thats the main thing that our thermostats are map controlled and ECU can be tuned in different heat ranges

I've found out that cars produced for Republic of South Africa has set in ECU to open on 95C and its set by BMW.

So, is there anyone who can tune our ECU's and find that map which controls thermostat to set desired values or is there somebody who can flash RSA program in S63 ECU?

This is right way to naturally lower our engine's temps

The way this works is the ECU can only open the thermostat, it can not close it. So it only has partial control, meaning it can only make the engine run cooler. Whatever the thermostat wax motor is turned to, is its baseline. The ECU can turn on the heating element in the thermostat that will in turn heat the wax motor and force the thermostat open and cool more.

A tune would be great but I have yet to find anyone with the knowledge to tune the thermostat.

[Leon S. Kennedy]

Originally Posted by Sophisticated Redneck

BMW Engineered this Tstat for emissions compliance, not performance or engine longevity. It is why they have the DME override on it to drop the temps when you step on it, then return to its normal crappy high temps during normal driving. Lowering engine temps will increase performance and engine life. Not to mention increase the life of all of the seals in this engine...Same valve guide seals that wear out due to high temps BMW lost millions in repairs on the N63 are also used in the S63 btw...

Anything BMW recommends has been filtered by Government Compliance, Management and Marketing. It is NOT direct from the engineers. Some of it is good, some of it is ABSOLUTE BS. Check on BMW's recommendation on oil changes for the 8 speed vs what the actual manufacture of the transmission recommends if you want just one example.

BMW engineers are brilliant, their management and marketing that have the final say....not so much.

You are absolutely right, nothing to add

[Leon S. Kennedy]

Originally Posted by Sophisticated Redneck

The way this works is the ECU can only open the thermostat, it can not close it. So it only has partial control, meaning it can only make the engine run cooler. Whatever the thermostat wax motor is turned to, is its baseline. The ECU can turn on the heating element in the thermostat that will in turn heat the wax motor and force the thermostat open and cool more.

A tune would be great but I have yet to find anyone with the knowledge to tune the thermostat.

We have to find person which can do this tune.

I couldn't find any additional info in internet about this tune

[Thecastle]

Originally Posted by Leon S. Kennedy

Ok, very good now we know that only tune of ECU can open thermostat on 90C

So, what tune we need or who can tune that?

The way the ecu commands the tsat to open is there is a heating element in the thermostat that heats the thermostat so it opens fully sooner. The reason no one tunes this is because the heating element isn’t designed to be used all the time and will burn out with constant usage. Tuners have tired, I’ve talked with some and found out the heating element burns out over time.

I have done the “90c” thermostat on my 4.8i, X5m and n63tu 550i. I’ve done bmw logic 7 and hamburger tech I mean Hamburg tech. Anyway I ordered 2 HT thermostats and installed them and both were defective. Didn’t lower the temp at all from the standard 105c. So I had to remove them and send them back. Tstat swaps are such a pain with that one bolt...

So I swapped logic 7 and never looked back. On the 550i It does not make a lot of difference. The car has other tools at its disposal to control coolant temps beyond the thermostat like grill shutters and etc. so it typically hovers at around 95-98c in cool weather and 105c when sitting in hot weather,

I think the cooler Tstat is a good idea for engine longevity, but it will hurt fuel economy slightly as more combustion heat is lost to the cooler cylinder walls, and it takes longer for the oil to get to full temp in the winter. There is also the concern the oil may not get hot enough in cold climates to evaporate out contamination.

I’ve done this mod 3 times successfully. I’d also recommend a turbo blanket and heat shielding for the rubber lines to help increase their longevity

But remember these are old cars and especially in hot climates the plastic under hood becomes embrittled. Cooling the temps helps, but plastic wears out.

[Leon S. Kennedy]

Originally Posted by Thecastle

The way the ecu commands the tsat to open is there is a heating element in the thermostat that heats the thermostat so it opens fully sooner. The reason no one tunes this is because the heating element isn't designed to be used all the time and will burn out with constant usage.

I have done the "90c" thermostat on my 4.8i, X5m and n63tu 550i. I've done bmw logic 7 and hamburger tech I mean Hamburg tech. Anyway I ordered 2 HT thermostats and installed them and both were defective. Didn't lower the temp at all from the standard 105c. So I had to remove them and send them back. Tstat swaps are such a pain with that one bolt...

So I swapped logic 7 and never looked back. On the 550i It does not make a lot of difference. The car has other tools at its disposal to control coolant temps beyond the thermostat like grill shutters and etc. so it typically hovers at around 95-98c in cool weather and 105c when sitting in hot weather,

I think the cooler Tstat is a good idea for engine longevity, but it will hurt fuel economy slightly as more combustion heat is lost to the cooler cylinder walls, and it takes longer for the oil to get to full temp in the winter.

I've done this mod 3 times successfully. I'd also recommend a turbo blanket and heat shielding for the rubber lines to help increase their longevity

But remember these are old cars and especially in hot climates the plastic under hood becomes embrittled. Cooling the temps helps, but plastic wears out.

Main thing is that when tuners tune maps in ECU and adjusting files, there is one map which controls thermostat that must be also tuned at desired temp.

My mechanic can tune our ECU but he says that there is 37000 maps in ECU and we should know exactly which one is responsible for thermostat.

[OllieX5M]

Im with redneck on this one temps are now just under the 210mark and when pushing the vehicle it gets just over 210 much better then before where it was always over 210.

[Dawgz]

Spoke with my tuner. He confirmed it's doable (dropping the coolant temps via tune) but advised against it for folks who live in somewhat colder climates like myself here in NJ.

[Leon S. Kennedy]

Originally Posted by Dawgz

Spoke with my tuner. He confirmed it's doable (dropping the coolant temps via tune) but advised against it for folks who live in somewhat colder climates like myself here in NJ.

So, it's very good news, can he perform this tune? Or does he have some ready tune for our hot S63?

In my country summer is over 40 celcius hot

[Thecastle]

Again, some of us have already tried a lower temp tune. The tune just turns on the heating element in the thermostat triggering it to open sooner same as the factory tune can. Leaving the heating element on all the time will cause it to fail earlier. That’s why everyone who wants this mod ends up eventually with a recalibrated thermostat.

Stock cruising temp is 105c. The lowest modified temp is 93c. Any lower and you’ll throw a check engine light for tstat failure. I’m sure a software person could block that code.

The biggest downside to this is lower fuel efficiency and lower oil temps, which can be a problem in cold climates. Though I don’t think it’s a big deal. Also if you run in m mode the car drops it’s temps automatically for better timing advance.

I’ve been running modified thermostats on a 2008 4.8i, 2011 X5m and 2016 550i and thus far haVe noticed no downsides, or benefits. I do notice on my 550i. It takes a very long time to have the oil reach full temp, like in cold weather, 30mins around town isn’t going to do it. X5M oil temps seem unaffected. Also the 550i keeps itself around 98c coolant in hot weather but still gets to 102-105c when sitting in traffic.