mini van eating alternators

In the last 2 years my 96 GMC minivan has distroyed 5 alternators. My former local mechanic and dealer tell me they can find nothing wrong. Would someone please give me something to try to fix this problem before it drive me nuts! ______________________________________________________

Dear Dipstick:

Please provide some description of what you mean by "destroyed".

Thank you.

Rodan. ________________________________________________________

I don't know exactly what configuration you have there. Some of the GM alternators such as the CS130 are pretty poor as far as reliability. If you replace them with rebuilts, some of those are TERRIBLE.

I always planned to duct some extra airflow to those alternators to cool them better, but never really got a chance to try it. Temperature and vibration can be killers.

Make sure your serpentine belt is absolutely correct for your engine configuration. I found some aftermarket ones that were about an inch shorter than they should have been. They would fit over the tensioner, but promoted water pump and alternator problems. Make sure your tensioner is working as it should.

All belts, pulleys, etc need to be aligned as intended by the manufacturer. I found one case a few years ago where dealerships had not reassembled the bracket system as it should have been after a warranty recall. Pulleys were not parallel or in the plane of the belt path, brackets were not tightened properly. Re-doing what these 'mechanics' screwed up cured that problem.

Use a VOM to determine if alternator is sufficiently grounded. A poor ground [ thick paint on bracket ] will shorten life of alternator. Over tightening belt will kill bearings.

V O M test, positive lead to positive battery terminal, negative lead to battery, check voltage, negative lead to alternator case, should be exact same voltage as at battery, lower voltage = ground problem