Fitment: 1997-2008 Ford F-150 2004 Ford F-150 Heritage What is a Fan Clutch? A fan clutch is a thermostatic engine cooling fan that can freewheel at low temperatures when cooling is not needed, allowing the engine to warm up faster, relieving unnecessary load on the engine. As temperatures increase, the clutch engages so that the fan is driven by engine power and moves air to cool the engine. .
