CV fan clutches are part of a vehicle’s engine cooling system and used to cool the engine by regulating the fan speed
At low or regular engine loads, the cooling airflow produced during driving is normally sufficient to dissipate heat from the radiator and work as an engine cooler. In this case, the fan runs at a slow rate or is switched off completely. If the load increases and the vehicle speed drops – e.g. when climbing a hill – there is a risk of heat accumulation due to engine overheating. Thus, the CV fan clutch is engaged to ensure that sufficient air flows through the radiator. The viscous clutch ensures that the fan speed is automatically adjusted to the level necessary to cool down the engine. This reduces both fan noise and fan power consumption, with the pleasant side effect of saving fuel.