[V8] alternator whine

dsaad at icehouse.net dsaad at icehouse.net
Mon Mar 28 15:36:20 EST 2005

If you have an oil leak at the right front head, that can drip onto the
alternator. I don't see how hydraulic fluid could be getting there though.

Alternator whine can be caused by lots of things. Did they put back the big
capacitor on the alt output posts?
If they did, it may be bad.
Also a bad diode in the alt can do this, as can a bad winding or voltage
regulator. In any of these cases, the problem should show up easily on a REAL
alternator tester and means you need a new alt. The new one may have failed
Real alternator testers (as opposed to what you typically find at Shucks) can do
accurate load tests and ripple voltage tests under varied RPM.
The parts store variety can do basic good/bad tests but that is about all.
You will find a good tester at a place where they rebuild alternators.


Quoting Steve Kramer <skramer at mac.com>:

> Fellow V8 listers,
> Since last I talked, my mechanic replaced the faulty alternator.  For over a
> month everything has been fine.  However, last week I started getting a
> whine under my hood. Also dashboard lights, get dimmer.  Whine lasts about a
> minute and everything returns to normal.  Whine doesn't increase pitch upon
> acceleration.  It's constant.  Doesn't happen every day but seems to happen
> with more electrical load.  Strange though - I'm not getting the dim
> Alt/Brake/Cat light.
> I don't have a problem since the alternator was replaced and this one is
> under warranty.  I don't know why an alternator would go so badly so soon.
> I do have the problem of the steering rack leaking pretty badly under left
> side at the firewall.  Could the alternator have gotten gunked up with
> hydraulic fluid?
> Steve Kramer
> 1990 V8q
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