Sounds like the alternator isn't getting enough belt speed to get enough charging. That would account for a passing at AutoZone and not on the car.

Hard to see it, but slippage between the parts of the harmonic balancer can cause this problem. Inner part runs at engine speed, if outer part (the pulley) slips it can squeal loudly. Drawing a line on the balancer that crosses the inner part and outer part will reveal the slippage.

Here's a test I used: The slippage will be worst when the electrical load on the alternator and the power steering pump is highest. That will be right after starting with headlights and heater and defroster on, and turning the steering wheel that uses the P/S pump.

See if starting and then waiting before turning on the electrical load items cuts down on the squeal. Then the only load increase will be from replacing the battery charge used by the starter. See if turning the steering wheel or increasing the electrical load raises the squeal.

Good luck,

Bob

:>)

It MAY be slipping, but,
if you put on new bushings and belts and you still have a problem, ( I assume you have a voltmeter and are checking the voltage at the battery), I would check the alternator ground (meter negative on battery -, meter positive on alternator case, car running, should read around 0.1 volts).
Check voltage at back of alternator, car running. Attach the lead before starting the car is safest, handy if you have a lead with alligator clips on both ends.
Check voltage at the starter terminal, this is where the lead for the alternator+ terminates.

--
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The rubber may have failed between the 2 metal pieces of the harmonic balancer. Draw a line across the 2 pieces of the HB with paint or crayon and see if it separates when the engine is run.
Dan

Hi,


I am having the same issue because I installed cheap Scan-Tech bushings. The pulley is silently slipping.


Goatman