This engine fan is driven by the engine crankshaft and pulls cooling air through the radiator core. It is mounted on the fan hub, which is driven by a belt or a viscous coupling, depending on the engine configuration. The fan blades are designed to move a specific volume of air at a given engine speed to maintain the coolant temperature within the operating range. A failing fan can cause the engine to overheat, particularly under load or in high ambient temperatures. As an original-manufacturer component, the fan is balanced to the same specification as the original assembly, which prevents vibration that can damage the water pump bearings and the fan drive.