Yea im wondering the same i got a 2014 c300 m276 engine, my temp light comes on like its overheating but its not maybe slightly temp goes up and drops and ac shuts off but goes back to normal no check engine light, im wondering if cooling temp is sometime working and sometime not, but iam assuming this can be the issue, but like he said not a diy job so i guess im goin to leave it alone

How did you know it was the coolant temperature sensor? Was the gauge saying overheating but the engine wasn’t? If not… I’m dealing with my gauge going barely a degree higher than operating temperature (overheating warning pops up) and then the gauge drops down to 80 degrees then stays there. I’ve replaced everything from the cooling system and this is my final straw? Were these the same symptoms? Please let me know! Anything helps!!!