I have a 1995 S-350 diesel. The car has an 80 degree C. thermostat in it. From when the car was new until last summer the two electric fans in front of the radiator would come on only on high speed. The engine temperature would rarely climb over 100 C, even in the hot summer. (In the winter it runs just over 80 C) Last summer the dealer told me the car is supposed to have a resistor that would allow the fans to come on at a low speed first then as the temperature rises would go to high speed. He said my resistor was defective and replaced it. Well, after that the car runs much hotter in the summer. It runs about 100 C and has to get over that before they ever run on high speed. Is this normal and good for the engine to run at this high of a temperature before the fans go to high speed?
136,000 miles and climbing