81 fan clutch
Thread Starter
Racer
Joined: Feb 2005
Posts: 269
Likes: 1
From: Eagle Rock Va
81 fan clutch
My fan clutch was bad, talked to the guy at Zip after measuring the radiator he said I needed the heavy duty fan clutch.When it arrived it was quite a bit bigger than the one that came off. Once it was installed,while going down theroad the fan was making a very loud whirring fan blowing sound.Is this normal,does yalls do this,its about all my radio can do to overcome this 
Thread Starter
Racer
Joined: Feb 2005
Posts: 269
Likes: 1
From: Eagle Rock Va
Originally Posted by PhotoVette1
A brand new fan clutch may do this for a day or so until it is broke in.
It also could be the reverse rotation clutch and it's engaged all the time.
It also could be the reverse rotation clutch and it's engaged all the time.
Intermediate
Joined: Nov 2005
Posts: 40
Likes: 0
From: Kent WA
You can buy a fan clutch at Autozone or whatever and it may be
close, but....
If you look at the variety of fan aftermarket fan clutches
available at your local parts store for, say, a small block
Chev application, you might find 5 or 10 different part
numbers. In practice, they were designed and "calibrated"
for individual engine/body applications.
My advice, get the right part number GM fan clutch (no, I don't
own GM stock or anything!).
Bela P. Havasreti
close, but....
If you look at the variety of fan aftermarket fan clutches
available at your local parts store for, say, a small block
Chev application, you might find 5 or 10 different part
numbers. In practice, they were designed and "calibrated"
for individual engine/body applications.
My advice, get the right part number GM fan clutch (no, I don't
own GM stock or anything!).
Bela P. Havasreti
Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
I replaced the one on my '81 as the free play on it seemed greater than the specs said in the manual (1/4"?). The new one was a lot tighter on the new one (measuring fore and aft movement at the fan tips) & it ran silently. After a few days it had obviously "worn in" as the free play was exatly the same as the one I took off 
The roaring sound is probably the fan locked up, or at least being driven hard. The viscous clutch on my DD has seized solid & there's a roaring sound at anything above idle (does the motor run cooler than it used to ie temp hovers at around the stat rating?).
The roaring sound is probably the fan locked up, or at least being driven hard. The viscous clutch on my DD has seized solid & there's a roaring sound at anything above idle (does the motor run cooler than it used to ie temp hovers at around the stat rating?).
Pro
Joined: Dec 2002
Posts: 560
Likes: 1
From: Mooresville NC
There are two different types of fan clutch, one that is controlled by RPMS and the other is controlled by a thermostatic spring which means when the radiator heats up the clutch engages. Make sure you bought the right one for your car. The thermostatic clutch is more expensive.
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
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