jokerswld34

Just noticed that my temp gauge was not reaching its normal position in the gauge. Temp was rising very slowly and only reached about 1/4. drove for about 30 min. As i drove it would actually go down in temp and then when I would stop or idle, it would reach about the half way mark. Not sure what this could be. Performance seems the same and I have full fluid. Could it be a bad sensor, bad ground, or a loose connector? is this a major problem or is it ok to drive for now until my service appt on Monday?

LILBENZ230

You're not getting a CEL? Sounds like the thermostat is bad (and stuck open) - common issue with these cars and not expensive. But that should give you a CEL.

How many miles do you have again?

jokerswld34

no CEL at the moment. i have 130K on the car (100k under warranty) and all driven by me. weird thing is i just let it idle in my garage and played with some of the sensor connections and the gauge started moving up to normal. exhaust gas seemed cold in temp tho if that means anything...

could be a fluke but i won't know until i drive it again tomorrow. hopefully its just a sensor. how many sensors does this car have to monitor coolant temp and is there a backup sensor to kick in if car is overheating?

LILBENZ230

I can't answer some of those questions, but if the thermostat won't open the car will overheat and you'll definitely want to stop driving immediately. The thermostats go bad, I've seen that a lot on this forum - they're not expensive.

BTW - You love your N54 engine as much as I do mine? The twin-turbo BMWs are tons of fun!

jokerswld34

hopefully it is stuck open as my temp seems to be staying between 1/4 and 1/2 and rises to normal during idle but reduces during driving. will i get a warning message if i am overheating considering the sensor seems a bit wonky?

and yes, i love the twin turbo motor (one of the best performing factory engines ive driven sans the exotics). its great fun but i have had some engine problems and cannot wait for the lease to be up. i didn't opt for the sport so the car has no oil cooler and as a result sky rockets the temp during spirited driving. truthfully, i love my merc more than the beemer, despite the unbelievable performance from the 335 motor....

LILBENZ230

Yes watch the gauge and also the MFD display should warn you to possible overheating.

I love my C230 more than I like the 135i, too.. but the 135i is the fun one. It's a Sport and has no oil cooling problems. At 9,500 miles it has been trouble free - not even a glitch. My C230 has about half the mileage of yours (65,700) and it, too, is trouble free.