Hello all!
I have a 2006 C280 with the M272 engine. about three months ago I replaced the radiator, thermostat and the engine cooling fan. At the time the fan would not come on causing almost overheating. I has worked well since then.

About two weeks ago the fan would run very loud starting shortly after starting the car. Searching the internet found that this is often due to loosing communications with the engine control computer.

When connecting my Icarsoft scanner to the car, It shows the the engine computer is telling the fan to come on at 89%. So the fan is doing what it is told.

The temp gauge on the dash shows about 90.

The scanner shows that the computer senses the engine temp at 104 degrees C. or 219F. that is quite warm! The car does not show any signs of actually getting hot. as a matter of fact, my laser thermometer only shows the outside of the thermostat housing as 170F.

Does this sound like the temp sensor on the back of the engine? I ordered one but not sure how to get into it to install. Looks like a pain job and want to explore any other possibilities first.

Thanks in advance.

Joe

Your on the right track, yeas its a pain , get a new o ring with your sensor

Thank you! I will make sure I have the o-ring.