Fit for: 1996-2000 2010 Toyota 4Runner 2006-2014 Toyota Hiace 2004-2014 Toyota Hilux 1994-1998 Toyota T100 1995-2004 2006-2017 Toyota Tacoma A cooling 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. .