C250guy

Hello,

My 2014 Mercedes C250 has eratic Temperature reading. It takes forever to warm up and the heat only comes on at highway speed. Once the engine and coolant system is fully warmed up everything works. But if idle or not running highway speed the engine runs cold. Especially with the heat on.

I installed a new Heat Valve and a new Thermostat.

The car will get warm and operate fine without the heat on. But if the heat is turned on the engine temperature still drops like crazy.

Does anyone have a manual pdf or something about installing the Thermostat on the EVO M271 engine? It is for the facelift version of the turbo 2014 C250.

I am unsure if the thermostat is installed correctly? I literally popped off the old one off and threw the new one in... what am I missing?

If I had some information specific to this engine and model I would be done. I can not find anything specific to inserting the new thermostat properly.

It might not be seated properly allowing the coolant to from the not warm engine into the heat cycle... idk something is not right with the thermostat and how it is sealing. I do have another new thermostat.

duchbk123

I understand the problem you describe. You access with Xentry, select "adaptation thermostat"; The purpose of this is to "teach" the thermostat to open and close according to the correct temperature.

You can contact Mercedes dealer, they will understand what I just said

alynch

My 2013 C250 exhibited the same symptoms. In my case it was just a simple thermostat swap out and the problems were resolved. Maybe check that the sensor connectors are fully seated? Here are the WIS instructions.