Fan noise, after fan clutch swap
 

Hey guys, I changed out the fan clutch a while back and can't seem to get rid of a new roar created by the fan blade now. been through four different clutches. The original had no noticable noise at all. The original clutch was also a lot thinner than any thing I have found at any parts house.
The roar is so loud @ 3,000 rpm it is starting to dround out the exhaust (Momma"s not happy).
My fan blade seems to match what is being sold for stock for a 1972 350 ci. w/ac.
Thanks for any suggestions.
David

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RE: Fan noise, after fan clutch swap
 

Is it a thermostatic or a centrifugal clutch? A thermostatic clutch as a little coil spring steel in the center which engages the clutch when it gets hot. You can actually hear the difference when it engages. The centrifugal has nothing in the center and just gets tighter with higher rpm. Sounds like thats the one you have.

RE: Fan noise, after fan clutch swap
 

I've noticed that the seven blade fans on A/C cars do roar when the clutch engages. I kept my five blade when I installed A/C and never had any cooling problems or fan roar.

RE: Fan noise, after fan clutch swap
 

thermastatic clutch with 7 blade fan, noise is there even when cold though.
Any body tried the reproduction parts from corvette america, maybe thinner clutch more slip?
thanks

RE: Fan noise, after fan clutch swap
 

Just so I've got this straight, you kept the same seven blade fan that was quiet w/ the original (OEM) clutch and all subsequent clutches have caused fan roar when engaged (hot) or disengaged (cold)?

RE: Fan noise, after fan clutch swap
 

That is correct.
wierd huh?
Tried one from Napa, Carquest two from O'rlies.

RE: Fan noise, after fan clutch swap
 

Question to the forum guys; Would these after market clutches cause the fan to turn faster than the original clutch allowed, with less slippage than the original clutch permitted?
When I had the factory exhaust on my '81, my fan WOULD sound louder than the engine/exhaust at certain RPMs, however, not to the point of being annoying.
Please keep us posted.

RE: Fan noise, after fan clutch swap
 

Hey Texas Jim you may be on to something just got back from a drive and car was about15 deg. cooler than norm.
was running 195 now about 180. Its 94 outside.

RE: Fan noise, after fan clutch swap
 

Does it free wheel when cold, ie, doesn't roar when first started with a cold engine?

RE: Fan noise, after fan clutch swap
 

Roars just as loud cold as hot.
I drove about 3 hours today, thought it might need to be broken in. nothin changed. well... my blood pressure did go down a few points:D

RE: Fan noise, after fan clutch swap
 

Hi Flying Low, The basic test for the thermo clutch is to start the car when cold, let it run for 2 minutes and stop the motor and see how much resistance you get when you try to turn the fan blanes, then restart the car and run it for 10 minutes ( untill hot ) then stop the motor, you should have more resistance now.
After trying 4 clutches I'll guess that yours is good.
If you still think it is to loud then you'll have to try a 5 blade fan. PG.

RE: Fan noise, after fan clutch swap
 

C3 Starship just brought up a good point! He says to check the line up of the fan blades. 1 or 2 may have inadvertantly got bent when the fan was removed, that could cause extra noise.

RE: Fan noise, after fan clutch swap
 

I will look at that, Thanks for all the help guys.
A grinding wheel balancer might tell me alot about that fan.:eek:
David

RE: Fan noise, after fan clutch swap
 

Sounds like clutch is always locked up then.

RE: Fan noise, after fan clutch swap
 

Ran the car for two minute checked resistance, then at ten minutes, no diference. after two minutes I cut it off. fan stopped dead.no free spin. I think that confirms it is locked up.:(
C3 , I did check the fan blades, they were all within about
.060", thanks.
David

RE: Fan noise, after fan clutch swap
 

So, does this mean that you have a bad (defective)fan clutch?
There's such little area for air to get to the front of the radiator in our C3s. I know that when I'm working on my 'Vette, and open the throttle all the way very quickly, I get that "wooshing" sound from the fan even just prior to the secondaries starting to open. Ofcourse at that second, it's time to close the throttle so I don't over-rev the engine. But that fan/clutch combo, even when it's working right, is a noisy joker anyway in our C3s, compared to other vehicles. I suppose it makes sense, that body set-up with the small air passages calls for a heavy-blowing fan/clutch combo.
Please let us know the final outcome ofyour "fan/clutch" situation. Good Luck and thanks for sharing.

RE: Fan noise, after fan clutch swap
 

Maybe it noisy now because the old one wasn't turning the fan fast enough to make noise.

RE: Fan noise, after fan clutch swap
 

Update....Seems to be freeing up with use on low end. It will spin when cold now.

RE: Fan noise, after fan clutch swap
 

So, is the noise quieting down?
I would think that if the fan is freeing up, you shouldn't have that overbearing roar any longer. ( at least until it fully enguages )

RE: Fan noise, after fan clutch swap
 

Quieter up to about 2000 rpm then roars. ( But I am useually pulling away by then):D

RE: Fan noise, after fan clutch swap
 

Have ya concidered a "Flex Fan"?

RE: Fan noise, after fan clutch swap
 

I have stayed up many nights dreaming of flex fans. I even had all the part piled up on the parts house counter and walked away.I have tried to keep the same look. I drove a good bit last nite. this clutch is changing. For the better.
Thanks again for everyones help and advise.
David

RE: Fan noise, after fan clutch swap
 

Hi again Flying Low, glad to hear that the clutch fan is working better. I took a nice ride last night too, went to a weekly car show in Stanley, held at a local hamburger joint. There were 3 other C-3's there but none of the owners could explain what your problem might be. As long as it's working better, good enough.
Enjoy your ride, PG.

RE: Fan noise, after fan clutch swap
 

Another option would be electric.

RE: Fan noise, after fan clutch swap
 

Hey guys this thing has really calmed down. And I thought driving her only helped my blood pressure. I'm looking for a 5 blade fan, to replace the 7 blade with, hope that helps too, thanks again.
David

RE: Fan noise, after fan clutch swap
 

Based upon my experience, a five blade will be quieter.