[locolobo]

I have been working on my 335d to give it the best TLC since purchasing 18 months ago with 32k miles. I now have 49,500 miles and I recently noticed that my car always runs at 80 degrees C (in the Torque app). No matter how hard I ran it, it would not go above 82C.

Several posts in the UK forum indicate this is not normal. The thermostat should open and maintain 88C - 92C when warmed up. I purchased one from BMW of South Atlanta and sure enough the metal part is stamped 88C. Note that they sent me 3 extra gaskets they recommended but were not needed. The new thermo comes with one o-ring for the smaller hose and the block gasket. The only one you need to buy is for the lower, larger hose. I just re-used the old one, though and it was in good condition, since they didn't send me a new one.

If you have ever done any work on your EGR system then the install is simple. (See other posts for this info). Remove the airbox, disconnect and remove the EGR cooler, pull off the retaining clips for the coolant lines, unbolt the thermostat integrated into the housing. Installation is the reverse of removal. It took me about 2 hours.

I did not drain the entire system and ended up losing about 5 liters of coolant, which I replaced with NAPA 1EXT extended life coolant (50/50 with distilled water). The OEM coolant is blue, FYI, and the NAPA is green. It's guaranteed to mix with all makes and models and cost $13.00 for a gallon.

Now I am am up and running at 88C. I hope this repair will result in improved fuel economy.

[Mark M]

Interesting. I've also noticed mine hovers closely around 80 degrees C all the time.

Was there a temp stamped in the t-stat you removed?

[locolobo]

Yes, 88C. Replacing it changed it to 88 ...

[taibanl]

Originally Posted by Mark M

Interesting. I've also noticed mine hovers closely around 80 degrees C all the time.

Was there a temp stamped in the t-stat you removed?

Mine is also consistently 80-82*. Is this below normal?

[Torqu3]

Originally Posted by taibanl

Mine is also consistently 80-82*. Is this below normal?

If ambient temps are at or below 50F then it's normal.

[Persian Whisperjet]

Originally Posted by Torqu3

If ambient temps are at or below 50F then it's normal.

Temp should be rock solid +/- one degree (two max). Some thermostat temps have been shown to drop over time. Yours may be on the way out. I replaced mine this weekend it was not diffiuclt but I don't have an EGR cooler to contend with.

[Torqu3]

Originally Posted by Persian Whisperjet

Temp should be rock solid +/- one degree (two max). Some thermostat temps have been shown to drop over time. Yours may be on the way out. I replaced mine this weekend it was not diffiuclt but I don't have an EGR cooler to contend with.

Friend of mine just replaced his with a brand new thermostat. He is seeing 83C or so. Ambient temp by him is below freezing most of the time. Ambient temp certainly plays a part in the car getting up to temp.

[Owen81]

You can check the coolant temp in the hidden menu if you're curious.
I haven't tried it but I think the steps are outlined in this video:

[taibanl]

Originally Posted by Owen81

You can check the coolant temp in the hidden menu if you're curious.
I haven't tried it but I think the steps are outlined in this video:

Thats how i checked mine. Item 07.00

Temps today about 42F