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.

 

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.

 

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

 

Sounds like clutch is always locked up then.

 

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

 

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.

 

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

 

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

 

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 )

 

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