A blown diode in the alt can also make a whining noise ... don't know exactly why, but it recently happened to me.

Dear Scott,

May this find you well. At 160K miles, the alternator doesn't owe much. I'd suggest getting it rebuilt, rather than awaiting failure - on a rain-swept, cold, dark and lonely road, when you're trying to make a flight.

Hope this helps.

Yours faithfully,

Spook

Sounds like the front bearing is starting to fail. Try removing the drive belt and spinning the alt. by hand and listening. Should be nearly silent except for a slight whirring/rustling (words fail me) noise. Anything like grinding or rattling is bad.

I bought a mechanic's stethoscope out of the discount trough of junk at a parts store and it has actually been rather useful in tracking down noise sources. You have to be careful what you bump it into or touch with it once it's plugged into your ears as it really amplifies sounds big time. Ouch.
--
Bob (son's 81-244GL B21F-M46, dtr's 94-940 B230FD, my 83-244DL B23F-M46, 89-745(LT1 V8), 98-S90, 77MGB and four old motorcycles)