Thermostat shot???, while I’m in there...

[Duc Hunter]

It appears my thermostat is shot as the car will warm up to 79°C and never get over it. Even after idling for 20 minutes and then driving on the freeway for 15 to 20 minutes in today’s lovely 75° Florida weather My understanding is it should be sitting between 82 and 88°C. Is this in fact a sign that the thermostat needs to be replaced? If I need to replace it what else should I be doing while I’m in there, other than the obvious coolant system flush? I’ll temperatures will read on my Carly application. Thanks for the help.

[andrewwynn]

Ouch tstat is in an absolutely moronic location of it's like the e92. The only thing related to it is the water pump.

Look for the official BMW repair guide they likely suggest to raise the engine a bit which would make it 20x easier.

[Duc Hunter]

Good advice, but do you think based on my data that my thermostat is shot? If I had a proper and working thermostat with my Carly app read 83 to 88°C of water temperature once it’s warmed up? That’s the real question.

[andrewwynn]

Originally Posted by Duc Hunter

Good advice, but do you think based on my data that my thermostat is shot? If I had a proper and working thermostat with my Carly app read 83 to 88°C of water temperature once it’s warmed up? That’s the real question.

That seams really cold to me.

[B4_685]

My 2012 E70 ran at 105C setpoint up to about 112-117 after a spirited run (read off obd2)


2012 E70 N63 50i

[TriX5]

Which engine?

[Duc Hunter]

Its a 2012 35d

[TriX5]

If you are at 100k or beyond I would do the coolant pump, the belts and take a hard look at the vibration damper. At that end of the block there is also the CCV hose, BMW asks quite a lot of money for a complete assembly. AARod sells only the flexible bit for about $20.


The 35D operating temp idling can be very low but at highway speeds it needs to be well over 80c. If you are consistently below 80, then better replace it.

[andrewwynn]

Not inexpensive but I agree with su the pump. You can keep the original add a spare even take with on long trips. Would be a suck day in some parking lot but could get you home until the fcpeuro warranty replacement comes in.

[Duc Hunter]

Originally Posted by TriX5

The 35D operating temp idling can be very low but at highway speeds it needs to be well over 80c. If you are consistently below 80, then better replace it.

Well I guess sits time to tack this project then. Yesterday I ran 30 min on the highway at 70-80 mph. Coolant temp was a steady 79-80C, occasionally hitting 82 on acceleration. Interestingly enough when I dropped down a few gear to rev the engine higher, the temp just went down. It was a balmy 65F during the drive too.

Thank for the help.