what repair is needed when the 92 buick century has a loud noise where the alternator is located?

check the belt real good and see if it is starting to shred around the edges of it,often they will slap and do this,it also might be that the clutch in the air compressor is going bad or the front bearing,and this will cause one to do this also,that would explain why its doesn't make the noise when the air compressor is kicked on,check it out i think you,ll find it,good luck with it.

Well, I'd loosen the alternator and remove the belt to see if the noise goes away. If so, turn the alternator pulley with your hand to see if you hear the noise. Replace the alternator once your sure it's making the noise. You can spray some water on the alternator belt while the engines idling to see if the noise goes away which means you need a new belt. Wear safety glasses in case the alternator fan self destructs!

it sound like the belt , if not maybe it's something in the ac compressor units, ac pulley ,ac clutch , maybe the comprasser is making that noise from the inside. but i think it's the belt that 's what it sound like .