M1009 eating alternators

[Napoleon_Tanerite]

About 2 weeks ago the Gen 1 light came on, and the volt meter was pegged about a needle width into the yellow band. Replaced the driver's side alternator, and life was once again good. Volt meter was pegged in the center of the green band, and voltage read ~14.2 at the battery. Well, today the SAME THING just happened.

Symptoms:
--Volt meter 1 needle width in the yellow
--Gen 1 light on at high RPMs, fades as RPMs decrease, out at idle
--Battery tests ~12.3 at the terminals right now with the truck running

The first alternator was the one that came on the truck, odometer was reading ~42k when it died. It took less than 1000 miles for the new one to die. It is feasible that I just got a bad part from the store; however, I'm concerned there is something else wrong that is causing alternators to die.

 

[acesneights1]

It's very feasible. Most auto parts store stuff is made overseas and junk. I'd have it bench tested at an Auto Electric re builder.

 

[Napoleon_Tanerite]

It's very feasible. Most auto parts store stuff is made overseas and junk. I'd have it bench tested at an Auto Electric re builder.

Sorry if I'm not following you-- you're saying it's feasible that I got a junk alternator? I really hope you're right, because I'm in DEEP over my head if I'm trying to track down some sort of phantom gremlin that is killing 100A alternators.

 

[SouthernSteel]

Ok i ran in the problem i went and got the Autozone alt the part number is listed a caddy for the 12 volt IM GOING TO STRESS DRIVERS SIDE ONLY and have been using it with no problem i only have the isolated ground alt on the pass side so far i have been on this combo for about 6 months with no ill effects

 

[Napoleon_Tanerite]

That's the alternator I have, the 100A listed for the late 70s caddys. I'm hoping I just got a bad one.