I'd like to start out by mentioning that not only did I put on all new belts and a new alternator when this started, but I've also since (like 6 months later) replaced the alternator and belt because of what seemed to be a bad bearing in the alternator.

Is this a common problem? The belt seems to be tight, and does this when it's looser too. Definitely the alternator belt, and now lately it goes away after the first 25 seconds if I rev the motor. Revving the motor doesn't make it go away sooner than that. Then it's gone for as long as I'm running the engine, but then upon startup again (even immediately) the squealing is there again.

It would be awesome if there was a serpentine conversion for these....

I do have power steering, AC, and the smog pump has been removed. All belts were replaced, but somehow I can't get the alternator belt to not squeal upon startup. If there's a remedy for this, or if it's a common problem I couldn't find it in the forums, any tips would be appreciated.

Thanks!

PS... it's a single V belt driving it.

 

It sounds like either the belt is not tight enough, is not the correct belt [width, depth and shape] or the pulleys are glazed.

There are instruments to measure the belt tension, but what I do is tighten to the point where the belt can be depressed about 1/2" on the longest run. Do not overtighten or damage to the bearings will result.

Take the belt off and using emory cloth, roughen the inside of the pulleys to remove any glaze.

The reason it squeals just after starting is that the alternator is working hard to recharge the battery after starting. Soon, the load on the alternator lessens and the belt stops slipping.

I have had excellent service with Goodyear Gatorback belts.

 

I bought this at O'Reily and sprayed it on the underside of my V belt.

Permatex® 80073 - Belt Dressing And Conditioner | O'Reilly Auto Parts

My belt is as tight as I want to make it. So that's not it. And I've tested my alternator, and have a new battery, so that's not it.
I just have bought a cheap belt.

I thought the spray was going to make the belt slip more and stop the squeak, but its actually sticky and makes the belt have more grip.

I think it costs more than the cheap belt I just bought. So, probably the best answer is to buy a better belt to begin with.

 

My 86-300 has an engine that came from an earlier year van (single belt driven alternator) and it, too, will squeal after starting, if it had to crank more than a second or two. Once the load is off the alternator squealing stops. I don't dare overtighten the belt, though ~Bill

 

I tried the belt grippy stuff on the old one, it didn't make much difference. The new alternator has a new pulley, and a new belt at the same time, so glazing isn't it. And the first belt was a brand name belt, the second one was a Napa Gold belt.

One thing that I did notice on the old alternator and belt (which turned out to not be the problem) was that the belt after a few months worth of use became more narrow, like it was wearing on the sides. I'm not sure what that can be.......

 

And old trick is to rub a bar of soap on the V of the belt. It worked for me. The tightness "spec" of the belt is 1/2" to 1/4" of slack.

 

Do you have one or two pulleys/belts on your alternator?