Batboard

truck is a 2000 tahoe, old body style w/ 350

shortly before my stock alternator died, i noticed an increase in the audible level of alternator whine coming thru what seems to be the factory stereo speakers....

well, GM replaced the alternator under my extended warranty, but now the whine is about 10x worse...

any ideas or recommendations on what i should tell them other than "it's whining"... lol



doug

Doug,

As far as the "whining", it should be blatantly obvious to any service tech worth his job. You really shouldn't have to describe it further. Just have them start the truck.

What are you running in the truck? There's no reason that you should have gone through another alternator as quick as you did (based on your post I presume it was quick). I'd make sure they diagnose it, and make sure it's not throwing codes. Also recommend they upgrade the alt from the 90-100 amp that's probably in there to a 130 or so as stock alts really aren't designed for lots of lights and radios. Make sure it's new and not remanufactured like the one they probably put in to replace the 1st one. It might cost you a few bucks, but it's worth the money.

-Ben

Doug,

Sorry, I'm tired. After reading your post again, was it 10x worse immediately after you got it back from them? If so, probably a loose ground somewhere. If not, could still be a loose ground, or the bearings in that alternator are shot and you need a new one.

Either way, take it back to the dealer and have them hook it up for diagnostics.

-Ben

Bearings make an audio whine??? Um....no.


More than likely, you have either one or more of the 6 recifier diodes open or shorted. On an OEM Americaqn vehicle, the case is the ground, so to have a bad ground, the alternator must be physically loose in it's bracket. Most modern alternators don't even have a noise supression capacitor, so you can also rule that out.

It sounds as if they installed a "Chico's Mexicano" rebuild in you vehicle that probably had no quality control or testing whatsoever.

jim wrote:It sounds as if they installed a "Chico's Mexicano" rebuild in you vehicle that probably had no quality control or testing whatsoever.

HAHAHAHAHAHAHAHA. Yea. I think he is right. Crapola into the engine bay = crapola out of the the engine bay.

Jim,

Just basing that 'bearing problem' or previous experience and what I was told:

OEM alt had the bearings fail, which in turn caused another part to fail, which killed the alternator and caused a horrendous audio whine. Sorry if I misinformed anyone

The reman they put in lasted less than a year, so I'm not a fan of reman auto parts. Insist on new!

-Ben

I had a '97 'Vic in the shop a while ago and the department INSISTED that I use an Autozone reman alternator in this car. I did.

It took three alternators to get one that actually would charge at idle and even it lasted for less than a week. A trip to Ford for a N-E-W alternator solved this problem.

Don't buy junk rebuilds. Most "rebuilders" replace only the failed part and nothing more. They paint it up really nice and market it as "remanufactred" when it really just had a new regulator or one brush installed.

Get a new one or have a reputable generator shop rebuild yours with good components from USA or somewhere else other than Mexico or Cambodia.

I've never had to have it done but from what I am told, most place that will actually re-build it correctly like Jim said can usually increase the output while they are at it.