2005 GMC Sierra serpentine belt

PGJCMARTIN

MEMBER
2005 GMC SIERRA
V8
4WD
AUTOMATIC
57,000 MILES

I am getting what I am pretty sure is a belt squeaking noise. I took a little tension off of the belt by moving the automatic tensioner a few times and the noise went away for a day or so and then returned. I went to buy a new serpentine belt and found that the belt varies depending on what amps my alternator puts out. I have looked under the hood for what alternator I have but cannot find the information anywhere. Do you know how I can find this out? The two choices appear to be either 105 or 145 amps based on going to an auto parts dealer. They did not know how to find out which alternator it was. Thanks.

3 Replies

OBXAUTOMEDIC

MECHANIC
3,711 POSTS

Hello,

Usually the amps are laser printed on the casing of the alternator, sometimes on top were it can be seen, but of course it can also be on the bottom were you cannot see it. The best thing to do it to take the tools with you to the parts store and remove the belt so it can be compared to the new one.

But before you do that just to make sure it is the belt. With spray lube in hand, with engine off spray the center bolt of the tensioner pulley, then start engine if sqeal is gone for a period of time then most likely it is the pulley bearing that is failing. If still sqealing and it has an Idler pulley turn vehicle off and spray center pulley and restart, if sqeal is gone for a period of time then could be the idler pulley bearing failing.

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