I randomlly get alternator squeel, hasn’t been constant, usually when I just start up my car… weird thing is though, its like a squeak more than a squeel… it will go pardon the lameness of this “Squeak nothing, squeak, nothing etc…” for about a block of travel, then back to normal… the belt is tight, I tightened it up as far as I could get it because I was getting constant squeel… I had replaced the alternator, once this year had it tested and everything, lol… is there a tool or something I have to use to torque the alternator up enough to stop this? (been using a crow bar lol)
u can also try some belt dressing
you are getting squeak or squeal or whatever u wanna call it probably from u over tightening it. the alternator tensioner bolts/nuts don’t have to be manhandled, there are torque specs for them. but its nothing ur hand can’t do. get the belt to the proper tension spec. that’ll eliminate ur noise issues… the CROWBAR WON’T.
when I first threw it in, I didnèt over tighten, and I did the ruler check my haynes tells me to, I had the proper play… it didnèt go away till I torqued it 
well u should only tighten it to the torque spec. aside from that… i’d adjust the tension by trial and error. loosen it up, see how that goes, then try taking up a good amount of the slack… etc. u man handling it isn’t gonna fix anything… unless it is a loose part. like stripped bracket bolts, and the vibration of the bracket rubbing against the stripped bolt can cause the squeal. many possibilities out there. i suggest u get a automotive stethoscope if u find that its not the belt. the water spritzer (spray bottle) can help determine if its actually the belt making the sound or something else. just make sure u know how to use it. and i’m referring to the spray bottle and the stethoscope.
Are you sure it’s the alternator? It could be the A/C tensioner that’s getting worn. Mine was squeaking like that too until it seized up and failed on the highway, breaking off and tearing through the A/C and P/S belts on its way out. I didn’t know it was the tensioner until it was too late 
I second that. I was about to suggest the A/C tensioner pulley but Neil beat me to it!
I had a squeel that varied with RPM’s and would come and go kind of randomly. It turned out it was the A/C tensioner pulley, I could barely turn it by hand it was so bad.
yeah Im sure its not it… reason… the belts not there because the tensioner is seized and Im waiting for a teggy with ac to pop out at the junk yard to get the part haha…im too cheap to grab a new one lol.
i never had problems ever with over tightening belts, but how’s the condition of the belts? could just be from normal wear and age which will make noise no matter how much you tighten the belt
bought it new with the alternator…