AlexAdams

Everything's fine.


97C fans cut in
87C thermostat opening temperature
82C, probably coasting downhill/overrun.

Azidaha

Hello team,

I feel sorry, to bump up that old thread, but it is still better than opening a new one about the same issue.

Recently, I bought a 535d with around 100k miles on it. I heard about the secret menu and decide to check the engine coolant temp, then I discovered the following:

(the following was measured at 2-5 Celsius degree outside temp)

- While driving in the city, with traffic jams and so it stays between 90-92, but when there is no traffic lights and no stop signs/cars it is going down to 60-70;

- While driving at the highway it stays between 64-74, never reach 90;

- Another weird thing is, that it takes a lot of time to get down to the four (4) " - " dashes on the RPM gauge. For example if I go straight out of the town it could take around 100 miles and still not at 4 dashes;

- The car blows hot air, and the air condition is working fine. It is warm in the car even not at Max fan temp/speed;


After a serious investigation I discovered, that my problem could be the EGR stat. Could you guys confirm the weird temps and stat replacement?


Kind Regards,
Azi

AlexAdams

Azi, nothing weird there. Both main coolant & EGR thermostats need replacing on your vehicle, the only result of interest is this: While driving at the highway it stays between 64-74, never reach 90 .


Is yours an auto? There is an additional auto transmission to coolant thermostat but that doesn't seem to raise it's head.

Azidaha

Hi Alex,

Yes. The car is equipped with automatic transmission.
I heard about the third thermostat, but also heard that it has no role in the main coolant temp.

Yesterday I replaced the EGR Stat, and there was a slightly improvement, but still not working as I expect.

I will definitely replace the main coolant stat during the weekend, since I have no more off days this week.

Will post the temps with the new stat as soon as I replace it.

Just curious, is it safe to drive the car like this - without reaching normal operational temps? I do believe that there is nothing dangerous to happen with the engine, but I’m afraid quite about the DPF filter and it's regeneration.

Azi

Tigr

Guys, BMW is using BEHR EGR thermostats. For my (E60 530d) car it is BEHR TE170. It is cheaper if you buy not at the official BMW service, but from somewhere else, like I did: EBay. I paid only ~19 € with delivery. And it is absolutely the same product what you will get from BMW!!!

Azidaha

True. Absolutely true.

I bought the small one from official BMW dealer and it was made by BEHR, the cost here in Bulgaria was 15,5Euro (O-Ring included);

I have checked the price for the bigger one, and it was 30Euro - again made by BEHR Thermotronic;

I can't believe the low price for such a car as E60, but it is as it is - can't be happier with it!


Azi

AlexAdams

Your results are as expected. You should not ignore the problem, the DPF will not actively regenerate in your current situation. You're wrong to say the third thermostat has no effect, they're just not a common problem (probably provided by the gearbox manufacturer up to a specification not down to a cost) not BMW.


It's my opinion that these poor quality thermostats, long service intervals, not changing the turbo oil strainer regularly are the primary causes of early turbo & DPF failure.

Azidaha

Hello everybody!

As I said, I will keep the thread updated in case someone else come to it through the search machines like I came.

Today I replaced the main thermostat. I bought a brand new BEHR Termotronics - that is the original one on lower price, just because it is not branded with BMW logo on it.

The temps finally reached the expected by me point. During the city and on the highways it stays the same - 92-94 Celsius degree (outside 2-4). The car reaches its operational temperature much faster, and it is much warmer on the inside. I am so happy with my new stat!

When I took off my old thermostat, I discovered that it was blocked open - that should be the reason for not reaching operational temp before.

It took me around two hours of work, so it was a nice car and owner experience as well!


Kind Regards,
Azi

AlexAdams

Regarding the turbo oil strainer I mentioned above: I was incorrect, some vehicles do have a separate turbo oil strainer in line before the turbo, it appears the BMW's don't. My confusion arose because by friends 320d E90 killed the turbo because the oil pump strainer was blocked (caused by excessively long oil change intervals) and sooty gunk in the sump.

sashah

Hi All

This is my first post on this forum so please forgive me for my shortcomings. Hope I am not hijacking the post but it seems related to this post so replying here. I am a bit desperate to see if some can help me with problem in cooling system after changing both stats. So here goes:

Background:
I recently bought Pre-LCI 2006 e60 520d M Sport and noticed that MPG wasn't so good (Around 28.5 Average) so after reading on forums checked coolant temperatures in hidden menu. (Which is supposed to be around 90 degrees?) The temperatures were reaching mid 60's Max.

So as some posts suggested I changed my EGR Thermostat first. This improved maximum temperatures by couple of degrees but didn't fix the issue.

After this I decided to take the plunge and change the main Thermostat too. I followed steps in following Video guide:

Until this point all seemed to go well. After re-assembling everything I filled up the expansion tank with coolant after tightening the drain plug under radiator. Then started the engine and kept topping up coolant as the air left the system. I kept doing this until I couldn’t see any bubbles coming through.

Now the problem:
After doing all above I took the car for a 5 mile spin but temperatures are staying around mid-50’s. Now I am a bit confused about what might have gone wrong. On a different forum some suggest opening the bleed valve on EGR stat which I tried too but no difference.
Next day one thing I noticed was that coolant temperature kept rising while in Idle but as soon as I drove the car it came back to mid-50s (it rose to about 70 when idle before I drove off)

I checked the pipes coming out of EGR and Main stats and they both seemed hot. But both of them were merging anyway so hard to tell which stat is letting coolant through. I also replaced the new EGR stat with old one just to see if it makes any difference but it didn't. I can't see any coolant leaks anywhere either.

Could my problem be related to system not been bled properly? I am inclining towards new Main stat being faulty? but can't say anything for sure..

Any clues?
Thanks