- Fan clutch
A fan clutch is a thermostatically-controlled device that exists as an integral component of the
automotive cooling system. When the engine is cool or even at normal operating temperature, the fan clutch partially disengages the engine's mechanically-driven radiatorcooling fan , generally located at the front of thewater pump and driven by a belt andpulley connected to the engine'scrankshaft . This saves power since the engine does not have to fully drive the fan.However, if engine temperature rises above the clutch's engagement temperature setting, the fan becomes fully engaged, thus drawing a higher volume of ambient air through the vehicle's radiator which in turn serves to maintain or lower the engine
coolant temperature to an acceptable level.Most fan clutches are
viscous or "fluid" couplings combined with abi-metal lic sensory system similar to that in athermostat .Normally fan clutches are fairly reliable, but sometimes they fail. A common symptom of fan clutch failure is overheating at idle or in heavy traffic. Bad fan clutches can also cause poor performance of the car's
air conditioning system because the fan also cools the air conditioner'scondenser , which is directly in front of the radiator.Another potential symptom of fan clutch failure (always drawing air at a high rate) in a cold weather climate is that the heating system blows lukewarm air never delivering sufficient hot air.
Wikimedia Foundation. 2010.