Belt squeal

jrwilson · jrwilson's Garage

I'm experiencing an annoying problem with belt squeal.

I have the Retro A/C installed with the heavy-duty alternator. It puts a huge load on the engine when it engages, and when the engine is cold it causes the belt to squeal really badly under acceleration.

It was so bad I converted to the Clewett serpentine belt setup, hoping it would give better grip and it did for a bit, but even after tightening it as much as possible even it's squealing when cold, even when not under acceleration.

Once it warms up it's less of an issue but still happens a bit. If I don't run the A/C it's less but still not 100%.

I've tried belt dressing and now I'm all out of ideas. Any suggestions?

unclebilly · unclebilly's Garage

Try a different brand of belt.

I had a similar issue once.

REVerend · REVerend's Garage

Have you looked at the belt alignment? Had that a similar issue with another car and that was the problem.

Bill Douglas · 08-10-2025, 09:18 PM

This stuff stops squeaking and also stops (minimises ) slipping.

Mike Czech · 08-10-2025, 11:40 PM

You might want to check the pulley at the alternator. Mine was also squealing, until I found out that my pulley needed replacing.

jrwilson · jrwilson's Garage

Just want to say that I'm not running the stock belt, I'm running the serpentine belt.

Duc Hunter · Duc Hunter's Garage

I am about to swap to this serpentine setup. My standard but squeals but only VERY rarely. Though I have worn away many fate teeth on the belt over the last 5 years or so. I think thats just tension and load. Now I'm curious what the community and you can come up with as a solution. This is a new one to me.

I like the idea of belt dressing to try. On another car it helped and only had to be reapplied once a year.

'78 SC · '78 SC's Garage

I have the Clewett serpentine belt drive also. I found the bearing in the idler pulley fit loosely enough that it could rotate in its housing. I used green LocTite to secure the bearing and no longer have the squealing noise that previoiusly occurred at all RPMs above an idle.

The serpentine should not be over-tightened. Also check the fan shroud clamp bolt torque (4.5 ft/lbs). Over tightening it can distort the shroud enough to contact the fan tips.