serpentine belt

99 mustang gt squeeling noizes coming from the serpentine belt when the engine is at normal operating temperature and only at idle. i thought i had a bad belt so replaced it and the noize is still there.

any ideas on what it could be? maybe the tensioner is bad?

Have you checked the bearings on the tensioner and the accessories?

Try Belt Dressing First If That Works Cool, But If Not, Selective Spraying Of Pully Beirings Might Help Isolate Where The Nosie Is Coming From. Good Luck