A Mercedes Benz fun clutch / fan assembly is usually located between the engine and the radiator. The fan that is attached to the fan clutch will cool the coolant in the radiator and maintain an acceptable temperature for the engine to perform. When the engine is sufficiently cooled, the fan clutch will disengage and thus will save the engine from using less energy required to drive the fan. When the temperature rises, the fan clutch will re-engage, and again cool the engine. A common symptom of a defective Mercedes fan clutch is when a vehicle overheats at an idle, or if the vehicle is at a standstill in traffic for a long period of time. Most clutches are viscous (Liquid Oil Filled) clutches that operate in conjunction a bi-metallic sensor, similar to the way a thermostat on a vehicle operates.
