Ordered an alt. from Schucks today, it'll be in by the time I get off work. $155.00 with the core deposit.No one ever responded to the "Why did it fail after on 84,000 miles..." question. I'm sure it was a chicken/egg thing. If the battery failed I suppose it could over drive the alternator and burn it up...

We did. A bad old battery can kill a alt.

 

It was old, 7 years old, which is a long time. Sort of like asking why 1 95yo died.

 

For more detail explination.

 

A battery (std lead acid) is a bunch of plates. Over time the plates shed material from normal cycling (this can be accelerated if the battery is not porperly bolted down). Eventually that material shorts out one or more sets of plates (each battery cell has plates in it). When the cells short out, the battery beomes a giant reisitor. this can overwork the altenator and burn it up. There are other ways the plates can be damaged too.

 

At this point a cell will no longer hold a charge.

 

http://www.mpoweruk.com/leadacid.htm

 

nipper

Had anyone previously used your car to jump start another car (or jump started your car)? Sometimes if not done correctly you can do damage.

You stated that the alternator had excessive ripple. This is different than a regulator problem and is what Skip and I mentioned may be the problem in earlier posts. The excessive ripple is due to bad output diodes. The old battery may have caused the alternator to work too hard and it killed some of the diodes and that causes ripple. There are a lot cases like this and with less mileage than you got. You should be good to go for a long time again with the new replacements. Be sure the new battery is fully charged before it is installed in the car.