Alright, so on my 93' W350 I've been having a really high pitched screaming/squealing noise that I narrowed down to the pulleys on the engine. It starts screaming at high RPMs and I've replaced the idler pulley and the belt tensioner which seemed to make the problem a little better. But this morning when I fired her up it was a little chilly and I heard her squeaking, so I popped the hood and I think it was coming from the alternator, but I had the alternator rebuilt by a local shop so I'm at a loss at why it would be that, or what else it could be? and are you able to replace just the pulley on the alternator?

 

Ithe pulley on the alternTor might be turning, but the bearing or bushing at the back may have seized. The same happened on my truck last weekend. Do you hear it as soon as the truck starts?

 

I usually don't, but I heard it as soon as it started this morning. But it was fairly cold, so i thought that might be why I heard it this morning, but other times I usually don't when I first start it

 

Go to the parts store and get a can of belt dressing. While the engine is running spray the belt with the dressing. Be careful of the fan blades.

 

Make sure all of the pulleys (Alternator, crank, power steering, air pump, fan) are true to each other or in other words, all straight in relation to their respective belt routing. I've had reman-rebuilt alternators with pulleys that don't quite line up exactly with the fan/crank which can create a squeal, especially at high RPM's.

 

I have used that belt dressing and it makes a really big mess. The best thing I have found is baby powder. Put a little on the belt as it is spinning and the noise just goes away.

 

I've heard of using baby powder, but since I always find belt dressing to work just I need it I've never given it a try

 

The best thing about baby powder is that it dries up any oil or grease on the belt.

 

Baby powder? No kiddin. Learn sumtin new everyday. I use a bar of soap. It works OK, also.

Next time i'm try'n the baby powder. I too, make a mess of things with the proper belt dressing.

Thanks!

 

I have used Di-electric grease for a long time and that works great. But with baby powder it just don't make as big a mess.