Fitment 1981 Datsun 810 1981-1983 Datsun Maxima 1990-1994 Nissan D21 1998-2004 Nissan Frontier 1995-1997 Nissan Pickup 2000-2004 Nissan Xterra What is a Fan Clutch? The clutch fan is equipped with a fan clutch between the pulley and the fan blade hub, and the working state of the fan is adjusted through the separation and engagement of the clutch. This not only ensures the normal operating temperature of the engine, but also reduces the power loss of the engine and reduces fuel consumption. How to Detect a Faulty Fan Clutch? .