serpentine belt

[tractorboy]

I have a base model Impala , 2003. How long is the serpentine belt supposed to last. I see what looks like a wear guage (marks) on the idler arm for the serp. belt.

[Iflylow]

I usually change mine about every 50K miles or so. If the belt has cracks, missing ribs, thread showing etc. its time to change it.

[la1]

I found in the factory service manual the first check is @ 150k miles