Ok well my old alternator had a noticable squeak even when spun by hand, so I swapped it out to a new Bosch one. It was fine for the past two days and today when I went to work. Absolutely no noise from it, then when I come home from work I have the loud squeak that I thought was the old alternator. It all of a sudden came back, without any changes since the alternator swap. Is it possible the new alternator has the same problem or was it just luck that the old one made noise and that it went away when I changed it.

 

did you check the belt?

 

Yah I mean it seemed ok, but I will change it out anyway now just to rule it out.

 

I know you said that you turned it by hand and heard the squeak from the alternator, but did you check the belt tensioner? I have replaced 2 of them on mine that became noisy.

 

Yah it didnt seem to make noise when it was spun and seems to be smooth in its range of motion. It was changed about 3k ago.

 

I am having the same trouble also with my 97 Blazer. I'm on my 4th alternator now. I will replace it and it will be fine for awhile. The millage varries between alternators. My problems started after I replaced the air compressor for the a/c. We installed an aftermarket a/c compressor and it made the beltalmost too short and it was harder to get on.I didn't have to jump iton or pry it on but the belt was at it's limit. Shortly after, the alternator statred squeeking. So I replaced the alternator and went up a size on the belt. Everything seemed to fit like it should. A year later, the squeeking started again. I thought maybe the tensioner had something to do with it. Replaced it and the alternator again. I have used 2 Delphi replacment alt's at $140. So I figured I go to another parts store withlonger warrenty and keep replacing them. Now the things won't last 3 months. It seemed that the front bearing went bad in everyone of them. There can't be too much belt tension on it. Got me stumped and really agrevated over the whole thing.

The last option I have to go buy a new GM alt. froma dealer. Now thats going to hurt.

 

Get a NAPA alt. They have a lifetime warranty. That is what I did and I am on my second one.

 

I litterally just put the thing on though so I wouldnt expect a brand new bosch with a lifetime warranty to fail in two days. It does charge better than my original delphi did.