when I start up the car, it squeals very loudly, then after it runs for a while it dies down but it does it every start up. I had to pull the alternator since it sounded like it was coming from there, so I replaced the bearing and it wasn't the issue. So could it be the belt pulley tensioner, since I know it's not even that old and I did not over tighten the belt. So I hope anyone out there had that issue and can point me what could it possibly be.

 

Put a big dab of dialectical grease on the UNDERSIDE of the main alternator belt. If it stops squealing you’ve found your prob.

 

baby powder. itll soften the squeal and not grease everything up with silicone.

does sound like belts are loose. also could be a separated damper ring. i had one on my 00 break loose. would scream whenever ac was on. drove it for about 6 months before i decided to look into the problem.

 

Belts and pulleys.

 

belt might be loose. check and see how it looks before tightening it, you may need a new one.