Hi I just replaced my alternator never had any belt squeal before, but now I do. I have tried tightening the belt and I think it is gone but the next day the same thing happens. If I add load like rear defroster, the lights will dim at idle and the belt squeals again. then within a about a minute the squeal goes away then comes back.

What can cause this.

When I adjust the belt am I supposed to loosen the top and bottom (nut) through bolts?

91' Accord

 

yes it will take the bind off the alternator and allow it to pivot

 

Ok then thats why the belt never seemed to tighten. I'll do it tomorrow.