Help *** Alternator *** - The 1947 - Present Chevrolet & GMC Truck Message Board Network

406chevy · 09-02-2002, 05:45 PM

I have a 71 chevy truck with new 396. My original alternaotr went out days before i made the swap to the 396. So i replaced it with a stock one from the Oriely Auto parts. The alternator was working when installed( discounnected the battery while running and see if it keeps going). After two days it was no longer charging. Went back to store and got another one, this time highperformance model. Same thing happens after 3 days of driving. it is no longer working. Had them check at the parts store, they confirmed that both were not charging when i returned. What is knocking them out or what should i do to fix the problem for good.

Sinister · 09-02-2002, 06:09 PM

sounds like the voltage regulator...

Longhorn Man · 09-02-2002, 07:06 PM

That, and/or the way you are testing them.
Removing the bat cable only tells you 1/3 of the story. It only takes 8 volts to run, and only a few amps. That is not the reading of a new alternator.
Replace your alternator, and your regulater, and use a volt meter to test it all.
Sometimes (not common, but very possable) by removing the cable, you can fry a diode inside.

09-02-2002, 05:45 PM	#1
406chevy Registered User Join Date: Jun 2000 Location: Houston,tx,us Posts: 33	Help * Alternator * I have a 71 chevy truck with new 396. My original alternaotr went out days before i made the swap to the 396. So i replaced it with a stock one from the Oriely Auto parts. The alternator was working when installed( discounnected the battery while running and see if it keeps going). After two days it was no longer charging. Went back to store and got another one, this time highperformance model. Same thing happens after 3 days of driving. it is no longer working. Had them check at the parts store, they confirmed that both were not charging when i returned. What is knocking them out or what should i do to fix the problem for good.

09-02-2002, 06:09 PM	#2
Sinister Between Trucks... Join Date: Mar 2002 Location: Los Angeles, CA. Posts: 3,830	sounds like the voltage regulator... __________________ Beat it to fit, Paint it to match...

09-02-2002, 07:06 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	That, and/or the way you are testing them. Removing the bat cable only tells you 1/3 of the story. It only takes 8 volts to run, and only a few amps. That is not the reading of a new alternator. Replace your alternator, and your regulater, and use a volt meter to test it all. Sometimes (not common, but very possable) by removing the cable, you can fry a diode inside.



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