I have a 1996 Chevy 1500 and it is making a terrible squeling noise from the alternator. Any suggestions?

 

When does it do it? i almost replaced mine because it was squeeling real bad but i put a new serpantine belt on it and it was fine it only sqeeled when i was going parking lot speed and turning sharp at the same time or sometimes when i first started it.

 

If it's the alt. replace it First remove the belt and start the engine to see if the squeal is stiil there as it might not be any of the belt driven accessories...also could be rubber build up on the pullys. Put a liberal amount of valve lapping compound on several of the pullys and run the truck .You may have to do this several times to get all the old rubber residue off of them. Replace the belt and get a new tensioner pully and that should solve the squeal problem.

 

If you are 100% sure its coming from the alternator it needs replaced, otherwise I'd start simple first and remove the belt, spin each pulley by hand and if any are bad you'll hear a growl/squeak.

 

take piece of garden hose, use it as stethoscope, pin point noise origin. Idler pulley is right next to alternator, and I already had mine replaced twice. Tensioner too. If alternator squeals, it most likely shows as battery blue light on dashboard, or whatever indicates battery drain.
But hey, don't replace alternator yet. You can, actually, buy bearings for it and replace them. Bearings and brushes. Costs you about 10 bucks to fix it. Also, there's a $6 worth capacitor on the side. If you buy a refurbished one for $200, that's exactly repairs they did, plus maybe some general cleanup to make it shine and worth the $$.