Fan Clutch for '64 Super Wildcat

[rexcrews]

Fellow Members,

 

You all were such help with previous posts about door skin removal! Thanks so much.  I now have a question about the fan clutch on my '64 Super Wildcat.  It makes a roaring sound at low speeds but seems okay at higher speeds.  The fan clutch was installed at some point in the past but it looks brand new and is a larger heavy duty type.  I am wondering if there are recommendations out there for replacement that will stop this noise. The clutch is tightish, but will spin about 3/4 of a revolution when cold.  But it has been making this sound since I purchased the car last summer, so weather does not seem to affect it.  Thanks! Rex

[rocketraider]

It may be working as designed.

 

A GM viscous coupled fan clutch should "roar" for a few seconds when the car is first started and soon quiet down. A properly working one will then engage and "roar" depending on underhood temperature. When the viscous fluid cools down the clutch will disengage and quiet down. It will cycle this way while the car is running. You may hear it cycle more often under low speed or extended idle conditions, but cycling at highway speed isn't unusual.

 

If it "roars" constantly and doesn't cycle it's bad. Let us know what it does at highway speeds.

 

 

[rexcrews]

thanks for this answer.  It sounds okay on the interstate at 50 -80, but at lower speeds, it sounds like you're stuck in low gear and the engine is torquing more than you're moving.  This is, I think, a newer Hayden fan clutch for a heavy duty application.  This is also a thermal clutch with a little thermostat in the center.  I appreciate the help! Rex

[71GS]

The HD versions are definitely louder. Try swapping it for the standard version. 

[avgwarhawk]

Two things, the HD clutch may have been installed for overheating issues. In short, covering up a radiator not up to the trash of cooling as well as it should. Or, it's the only clutch the previous owner could find. So, find a standard clutch and hope it cools or replace the radiator so the HD clutch does not need to work so hard. 

[RivNut]

Shouldn’t ‘howl’ until the thermal unit gets hot enough to lock the clutch.  This usually happens at lower speed when cooler air is not moving through the radiator.

[RockinRiviDad]

Your heavy duty fan clutch isn’t broken. It’s doing exactly what it was designed to do. I did a write up about this on my build thread. Switch it back to a standard clutch & you’ll be happy

 

Here are screen shots & a part number for the standard fan clutch u need

 

 
 

 

 

 

 

Edited February 18, 2022 by RockinRiviDad (see edit history)