PeachParts Mercedes-Benz Forum - View Single Post - Installed new thermostat, but problems....

Ali Al-Chalabi · #12 03-13-2004, 12:48 AM

If the engine is not getting above 82C with the new thermostat, I would take it to the dealer, it is not functioning as it should.

If you want to verify proper operation for sure, or to check a new thermostat before installing it you can suspend it with a string so it does not touch the bottom in a pot of boiling water with a thermometer in the pot. Just put it on the stove and watch it open. Of course, this is easier to do before the thermostat is installed.

I have noticed at least in my C280, that as the thermostat ages is seems to gradually creep towards a lower opening temperature. The last 2 thermostats in my car worked exactly as they should have at first but then after about 3 years or so seemed to be opening about 5C colder.

82C in itself is not that cold and not really a problem, but if the thermostat gradually opens at a cooler temp as it gets older, will your engine be running and 75C in 2 or 3 years? That would be too cold.