Need help diagnosing a problem on my spare car. The serpentine belt on my Pontiac G5 has broke 3 times recently. The first time I simply assumed it was an old belt so I replaced it (not easy on those cars). The new belt broke after just a few minutes. I realized that the AC was on when I started the car so I turned it off before replacing the belt again. Everything worked fine for a few short trips until I turned on the defroster one morning, The belt broke within seconds. I'm not going to change the belt again without knowing what else is wrong. Could it be the AC compressor, the AC clutch, or something else?

Something is freezing up. Start with the compressor.

I'm surprised you're not hearing some kind of dreadful sound while this is happening.

From this I gather that the guts of the AC compressor are seized up or close to it. AC on, broken belt. Defroster on (which runs the AC compressor), broken belt. No AC and no defroster, good belt.

A really easy test would be to drive around for a couple of hours without turning the AC or defrost on and see if it does it just fine.

Thanks for the feedback. That'* basically my logic as well. Just figured I'd bounce it off of a few others before I soak money into a new compressor.

Since the last belt change the car has been out for 3 short trips totaling about 30 minutes, all without the AC or defrost on. As soon as the the defrost was turned on...belt breaks. This is an extra car and doesn't get a lot of road time. I'm thinking that why something seized up.

Thanks again!

You're welcome!

Let us know how it turns out!