RAM 2500 Truck 2WD L6-6.7L DSL Turbo (2010)
Fan Clutch: Description and Operation
VISCOUS FAN DRIVE
A thermostatic bi-metallic spring coil is located on the front face of the viscous fan drive unit. This spring coil reacts to the temperature of the radiator
discharge air. It engages the viscous fan drive for higher fan speed if the air temperature from the radiator rises above a certain point. Until additional
engine cooling is necessary, the fan will remain at a reduced rpm regardless of engine speed.
Only when sufficient heat is present, will the viscous fan drive engage. This is when the air flowing through the radiator core causes a reaction to the
bi-metallic coil. It then increases fan speed to provide the necessary additional engine cooling.
Once the engine has cooled, the radiator discharge temperature will drop. The bi-metallic coil again reacts and the fan speed is reduced to the previous
disengaged speed.
