Hi,

I have a 1993 Chevrolet G20 3/4 ton Van I just replaced the Alternator and the Serpentine Belt, I checked the Serpentine Belt path and pullies to insure it was in all the correct grooves, and I made sure it was routed correctly and used the tensioner. But every time I start the engine, the Serpentine Belt flys off,

Please, any ideas would be greatly appreciated as I am at my wits end as the belt and alternator are both brand new.

 

If it's the right belt, and new, you need to recheck the routing. Also do all the pulleys ect. line up?

 

I bought a serpentine belt at Autozone quite a while ago and they gave me the wrong one, it was a little too big and squealed all the time. Make sure you have the correct belt and that the tensioner is tensioning the belt correctly.

 

Yes all the pulleys line up. And I have rechecked the routing many times. and the tensioner is still pretty tight as it takes a lot out of me when I loosen it to put the belt on and I release it slowly.

On my G20 Van I am using the diagram on the top right of this picture

 

The only difference is the alternator and the serpentine belt. Examine them carefully. Make sure the correct pulley is on the alternator. If you still have the old belt, try putting it on.