Commander 2WD V8-4.7L Flex Fuel (2009)
Fan Clutch: Description and Operation
Viscous Radiator Fan Clutch - Description
DESCRIPTION
CAUTION: Engines equipped with serpentine drive belts have reverse rotating fans and viscous fan drives. They are marked with the word
REVERSE to designate their usage. Installation of the wrong fan or viscous fan drive can result in engine overheating.
CAUTION: If the viscous fan drive is replaced because of mechanical damage, the cooling fan blades should also be inspected. Inspect for
fatigue cracks, loose blades, or loose rivets that could have resulted from excessive vibration. Replace fan blade assembly if any of
these conditions are found. Also inspect water pump bearing and shaft assembly for any related damage due to a viscous fan drive
malfunction.
The thermal viscous fan drive is a silicone-fluid-filled coupling used to connect the fan blades to the water pump shaft. The coupling allows the fan to be
driven in a normal manner. This is done at low engine speeds while limiting the top speed of the fan to a predetermined maximum level at higher engine
speeds.
An electrical cooling fan located in the fan shroud aids in low speed cooling, It is designed to augment the viscous fan, However, it does not replace the
viscous fan.