how does the clutch fan work?

[into69z]

I want to know if anyone knows how to test a stock fan clutch? I had a few trucks, an 86, 89,and 96 all 3/4 ton with big block and heavy duty cooling. When those fans locked up, it sounded like you were turning 10,000rpm-till they cooled off-then back to normal. I have my 69 with a big block and the 4 row radiator,a/c, seven blade fan and a new fan clutch. I don't over heat until I get into stop and go traffic-it does not boil over,just the temp gauge goes to the middle. Are the fan clutchs all the same or are the newer ones designed diffferent? would the new ones fit the old trucks? How can I tell if my new clutch is performing correctly? Anyone have any idea about how much cfm's are produced with the stock system?

[Stocker]

Originally Posted by into69z

I don't over heat until I get into stop and go traffic-it does not boil over,just the temp gauge goes to the middle. Are the fan clutchs all the same or are the newer ones designed diffferent? would the new ones fit the old trucks? How can I tell if my new clutch is performing correctly? Anyone have any idea about how much cfm's are produced with the stock system?

If it doesn't boil, I wouldn't worry about... it's not overheating. Better units have a bimetal thermostatic spring on the front.

Here's a couple sites with good info:

http://www.2carpros.com/how_does_it_..._fan_works.htm
http://www.aa1car.com/library/cooling_fan_clutch.htm

[into69z]

Thanks! Stocker-Steve

[msgross]

You could replace it with a non-clutch fan or add an electric fan to assist your mechanical setup

[Stocker]

Originally Posted by msgross

You could replace it with a non-clutch fan or add an electric fan to assist your mechanical setup

Assuming a proper clutch fan and a good cooling system -- including a shroud -- in theory it shouldn't overheat. If it does, adding an electric ought to do the trick for sure. But I would personally never replace a clutch fan with a fixed mechanical fan.... just my opinion.