99 Montero Sport 3.5L 6 cyl - BAD ALTERNATOR!

Hello. I just broke down for a 3rd time with the same symptoms. The alternator fails every 4 months. While the car is on… interior lights come on and the acr dies. No hazards or anything!I have had the guys at Firestone replace it and they are so nice they do it for free! I’m sure this gesture is going to run out… The battery has also been replaced. Is this electrical? Should firestone be able to figure this out I’m worried because I havent talked to anyone there and my car is in their lot… I guess I’m just worried about what their answer may be this time. I already paid for a new alternator & battery!

Repeated failures of the same part in a situation like this usually means that someone is overlooking something; often something simple. They’re treating the symptom rather than the cause.

By interior lights do you mean the dashboard warning lights?
Have these alternators actually been tested and verified beyond any doubt about whether they’re good or not?
After the car dies can the engine be physically cranked over with the key even though it may not run?

There’s not enough info to make much of a guess but offhand I’d say there is a problem with either the ignition switch or a fusible link in the charging circuit.
(The link is a fuse type arrangement that allows current to pass between the alt. and battery to keep the alt. charged. Heat can cause these to fail; either permanently or erratically.)

It’s also possible that the fusible link that provides power to the car’s ignition system, etc. could be failing for the same reason.
Here’s what they look like

These links have clear plastic covers and many times, not always, a careful inspection may show a pinhead sized drop of solder on the end of the wire. If a drop exists this usually means the link is failing as age/excess heat is the cause.
An alt. that has failed in the past can take out a link as can poor jump starting of a car or a failing battery. Hope some of that helps.

Just my 2 cents but my opinion of Firestone is not very high at all.

Interior lights = dash warning lights. Sorry - I was thinking a mile/second last night. Alternators may/may not be good. The guy at Firestone seemed to think it was the alternator again… so he may just replace this once more. - not solving the problem -
I live in North VA. Where can I take this car to get problem resolved…? I’m at wit’s end with it. (Wife’s starting to bug me about new car… I can’t see spending $20k when the problem seems to be easy…Provided it can be fixed.)

If you are near Springfield/Newington area, check Car Talk Mechanics files at the home page. There are several good independent mechanic recommendations in that area listed there.

I just don’t see this many alternators being faulty.
Since it may be claimed the alternator is faulty yet again you might try this first.

Go down there with a small screwdriver, short length of coat hanger, etc. (any kind of ferrous metal), raise the hood, and turn the key to the RUN position.

You should see the red alt./battery warning light on.
If the light is not on, this means there is either a fault in the voltage regulator (part of the alt. or there is a burned out bulb/poor bulb connection. The latter can cause a good alt. to not charge.

Since I’m assuming here the light is working, and with the key still on, go around to the alt. and lightly touch the front of the alt. pulley with the piece of metal you have.
If you feel a magnetic attraction by the pulley then odds are the alt. is good and the circuit between the alt. and batt. should be inspected. (that circuit involving the fusible links)
This simple test is not 100% foolproof but most of the time it is.

At this point I can’t see trading cars if this one is in good condition, other than this alt. annoyance.
Also at this point, I don’t know how they’re coming to the conclusion the alt. is faulty or how any diagnosis was done, if at all.

There are a number of things that can caus a car to die randomly not related to the alt.
Failing fuel pump, ignition, fuel pump, etc.
There’s not enough info known about any codes or details behind the dying to make much of a guess.