VW alternator failure

2000 Golf

The other night, I was driving along and had pretty classic alternator failure–dash lights came on, then failed, car stopped and wouldn’t turn on again. I had it towed to the nearest shop (I’m new to the area, so I don’t have a trusted place yet, and didn’t have time to look one up). They replaced the alternator and changed the oil. They said the battery was fine, and that I shouldn’t have any more problems.

The car drove fine on the way home, so I parked it and didn’t think about it again. That was the day before yesterday. This morning I tried to turn the car on, and everything seemed fine for a couple of seconds, but then the tachometer needle dramatically dropped and the car quit again. I tried a few more times, with the same result.

Before I call the shop back to complain, I’d like to get some ideas of what might be going on. I do not know what I’m doing, but I’d like to go in as informed as possible, and I can’t afford to replace more expensive parts! Any advice would be much appreciated.

First off, don’t start by complaining. Just call them up and let them know what happened and see what they offer since they just repaired it.

The replacement alternator may be bad, or it may be that the alternator was never bad and instead there is a wiring fault to it. There are some simple in-car tests to determine where the problem is.

Good advice from both of the above posters. As a guess I would say the replacement alternator has failed. Possibly some of the output diodes inside the alternator have gone bad. You should have a warranty on the part at least if that is so.

Sounds Like You Basically Diagnosed This Yourself And Asked For An Alternator Replacement. Is That What Happened ?

I’m just wondering if besides changing the oil (You must have requested that, too.) and checking the battery, any diagnosis of the charging / starting system was done. What do you think ?

Was the alternator actually verified to have failed in the way that caused you to lose power (dead battery & no charge) at cruising speed ?