More alternator problems

[jelloslug]

I replaced my alternator 2 weeks ago with a NAPA rebuilt unit. I am now starting to see similar problems to what I was seeing before with the old unit. At idle with very little load on the alternator it will put out 14.2 volts. When I put a heavy load on the electrical system (headlights, max A/C, etc.) the voltage drops fast (2 volts or or more) and I start to get alternator noise over the radio and flickering lights. At the same time the alternator gets very hot fast. I unhooked the alternator and the car runs with no electrical issues (other than it not charging). Does my diagnosis sound correct? I hate taking off that alternator just to have it checked.

 

[wood_e]

autozone should be able to check your alternator with it in the car... just as an FYI

 

[jelloslug]

Hummmm.... I did not know they could check it on the car.

 

[Gen2Gen3WhatNxt]

what about the voltage regulater? I know they are very low cost, ive replaced one when I was having alt problems in my old 90 Slo GL. fixed it right away too.

 

[jelloslug]

The regulater is internal on the SHO alternators. I had the regulator melt in an old '87 GL I had long ago. Anyway I wnt back to NAPA and they checked it, it tested out bad and they ordered me another one. It should be here today; I will have them check it before I install it.

 

[HopefulSHO]

Anyway I wnt back to NAPA and they checked it, it tested out bad and they ordered me another one.

Disturbing how many people I've heard get alternators bad out of the box. Witch one did you buy? Napa lists two different (same amp) Napa-brand alternators for my SHO; Standard and "Supreme". I got lucky (or did I?) and a Supreme was installed on my car only a few months before I bought it.

 

[jelloslug]

I do beleve it was the supreme

 

[HopefulSHO]

I got lucky (or did I?) and a Supreme was installed on my car only a few months before I bought it.

BTW; I didn't get lucky. Mine died today.

 

[jelloslug]

In the end it turned out that the alternator was not the problem. The 2nd new alternator tested good out of the box but it did not fix the problem. I took teh 1st new alternator in and had it bench tested it it checked out OK. It turned out the ring terminal that connects to the alternator was making a very poor connection to the alternator and the wire. I replaced the connector and everything seems OK now.