1997 Chevy Lumina Chevy Lumina engine noise

I have found a great diagnostic tool for this is a stethascope like dr's use I take the round part off the end and that allows me to leason thou it while pointing end a rotating componets like the altanator, power steering pully, a/c compressor pully. Where ever I hear it more thats where the problem exist. Mind you that you are aiming the end at moving parts a good quik diagnostic practice but pay attention to moving parts, Possably a bearing in the altanator. If so to save money, take it out yourself, and carry it to altinator/ starter repair shop and tell them you want a rebuid and a tall them the noise it is making a lot cheeper than a new altanator and it will last just as long, Depending on where you take it it will probably have warrenty on the workmanship.