Clutch fan

[Richard Cooper]

I noticed there is a BIG difference when comparing my clutch fan to another 81. Mine is very hard to turn (when engine is off) a friend also has an 81 and his is very easy to turn. On his the fan keeps rotating by itself for a few seconds, but mine is so hard to turn that as soon as you stop pushing it it will not turn on its own. Can someone tell me which one is normal? I found this difference while trying to locate a vibration. There is about 1/8 of an inch of play in fan when moved from side to side. I have to check close to make sure the play is not from the water pump, but I wanted to find out about the clutch fan first. Thanks in advance.

 

[78SilvAnniv]

I believe the clutch fan should spin freely and not be hard to turn. It should also spin several revolutions on its own when the engine is turned off and not stop immediately.

My understanding of the clutch fan is that as the temperature goes up, the viscosity of the fluid in the fan clutch changes and is what controls how much spin the fan has in relation to your engine rpms. The fan spins at maximum at low speeds and rpms when it is most needed, and (my understanding) 'slips' when at higher speeds and rpms because the forward motion of the vehicle forces the air through the radiator for cooling.
Heidi

 

[Richard Cooper]

Heidi,
Thanks a million. I am going to buy a new clutch for the fan today. Now that you mentioned it I do remember seeing the fan spin after the engine was stopped, mine does not do that anymore. Thanks again, this is a great place!

 

[61 Silver]

clutch fan

Hi!



Get your engine up to normal running temperature. Have someone turn it off as you watch the fan blade. It should not turn more that 4 to 5 revolutions after engine is shut off.



Ray