Is my alternator bad...conflicting opinions?

J

jrm94mark8

Registered
For quite some time now my battery light flickers on and off. It's very random with no real pattern. I initially had someone look at when I was having some other repair work done and he said it was a loose cable and tried to fix it by tightening the cable (somehow??). That didn't fix it. I recently had some other work done and had this other mechanic check it out. He reported that he was checking the alternator and reading it is was registering over 15 volts which means it's the alternator. This seems high to me and I tend to agree with the later opinion but I don't know for sure.
I'm hoping to get some ideas here so I can get this done. Any help is greatly appreciated.

Thanks for any info-
 
How many miles are on the current alternator? The pre 96 units are relatively unreliable 120amp units that last about 80-120k miles. If you car falls within that mileage you can almost assume with certainty that if your charging light comes on it is the alternator.

Make sure to get a FORD rebuilt unit since the auto-parts store units are VERY unreliable and many have gone through several replacements a year.

FYI go for 96+ mark VIII or Mustang Cobra alternator it is going to be 130amps.
 
Well, the one on the car is not too old. I have 97K on the car (94 Mark) and I'm guessing it was about 15K ago judging by how many miles I put on the car a year. That puts it in the over 80K range. I bet the one I got was rebuilt multiple time as you said or just not that good in general. The car died and I had it towed to a Shell station for the fix. I am planning on getting a Motorcraft but just want to be as sure as I can.

So it's probably the alternator-
Thanks-
 
Usually the alternator creates a low voltage problem. To be sure, go to one to autozone or similar since they offer free electrical testing. They should be able to tell you if it is performing up to par.
 
Yes, the mechanic is probably correct. When my last alt failed, my aftermarket battery gauge PEGGED at 16 volts.....needless to say I shut the car off immediatly because I didn't want battery shrapnel all over my engine.

If the regulator in the alternator fails open, it will not have anything to stop it from overcharging. If it fails closed, it won't be charging at all, or very very little.

Max.....just a little FYI.....not ALL Motocraft alternators are made by Ford....most are the "mitsubishi" alternators and are garbage. I'd HIGHLY recommend getting your alternator rebuilt from a starter/alternator rebuilding shop. Given it will take probably 2-3 days, atleast you'll have peace of mind that it wasn't on an assembly line in China.

I had mine rebuilt locally, and its worked great ever since...and that was after warrantying about 5 alternators through my shop.
 
Alternator Longevity on a Gen II

Alternator Longevity on a Gen II

My '98 LSC just turned 200K Km on the weekend. I'm wondering how long the alternator's generally last on the Gen II's?
 
Honestly.....it depends which "one" you have on your car. The Mitsu one or the Ford one.......if you got 200k and its original, you're sitting VERY pretty and I wouldn't jinx yourself by starting to worry about it!
 
J, I don't know if you noticed but he has 200k kilometers, not miles. All 96-98 Mark VIII's come stock with the Ford 130amp alternator.
 
Oh....lol.

As far as I knew, there was two manufactures for Ford alternators. Both are stamped "Ford" but NOT both made by for, but FOR Ford by someone else. Outsourcing....and Mitsubishi made them for all years. I may be wrong, but thats what I've seen on the boards and thats also what the alternator builder told/asked me when I was talking about upgrading mine. He said the Mitsu ones are kick a** and about the best you can get "stock". He builds a lot of them for the Cobras and even the stock Stangs so I tend to believe or listen to him because he knew his stuff before I even had to tell him what I had.
 
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