Fan Clutch Symptoms

Used as a coupling device between the water pump shaft and the fan, the fan clutch is designed to improve the efficiency of the cooling fan, saving energy and reducing noise. A clutch allows the fan to engage or disengage as needed. A failure can cause the clutch to either fail to engage or to lock up.

Engine Overheating

Most drivers will recognize the signs of an overheating engine, however many do not realize that the fan clutch can be the cause. One of the main symptoms of a bad fan clutch is an overheating engine. The fan's efficiently will decrease as the fan clutch ages, and it will eventually not be capable of cooling the engine. The engine will overheat.

Bad Bearings

At times, you may hear the sounds caused by a vibrating or wobbling fan while you're driving. Check the fan while the vehicle is in park or neutral with the engine turned off. If you feel a side-to-side looseness, or you can make the fan wobble, the clutch needs to be replaced. The fan bearings are worn out. This will also cause premature failure of the water pump bearings.

Bad Clutch

The clutch may be worn out. With the engine off, give the fan a spin with your hand. There should be resistance. If the fan turns more than 1 to 1-1/2 turns after you give it a spin, the clutch is worn out, and needs replacement. If the clutch isn't engaging, the fan won't cool the engine.

Lock-up

If the temperature-sensing apparatus that governs the clutch in a thermal fan fails, the clutch will not disengage. You may hear a roaring noise at high engine speeds. With the engine turned off, attempt to spin the fan. If it will not turn, the clutch is locked, and needs replacement. This will not cause overheating, but will reduce engine power and mileage.