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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 232 (Engine Cooling System) >> Description and Operation >> Cooling System Description and Operation >> Cooling Fan and Clutch

Cooling Fan and Clutch

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Savana Special, 2003 GMC Savana Camper Special, 2003 GMC Savana, 2003 Chevrolet RV Cutaway, and 2003 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

The engine cooling fan and clutch are driven by the crankshaft via the drive belt. The cooling fan draws air through the radiator to improve the transfer of heat from the coolant to the atmosphere. As the fan blades spin, they pull cool, outside air past the radiator core. The fan clutch drives the cooling fan. The fan clutch controls the amount of torque that is transmitted from the crankshaft to the fan blades. The clutch allows more torque to engage on the fan when the engine operating temperature increases and/or the vehicle speed is low. As the torque increases, the fan turns more quickly. The fan clutch decreases the torque applied to the cooling fan when the engine temperature decreases and/or the vehicle speed is high. As the torque decreases, the fan speed decreases.