jonwb

Hi... really lost here...

My wife and I have taken her Mustang into two auto service shops within a week trying to get her AC working. The first time the car died while idling and they found the alternator was bad. I had just put in a new PepBoys ProStart model last year. They charged the battery and we got it home. I took the old one out and installed a new onsite-tested ProStart rebuilt part into the vehicle. Afterwards the battery console light would not go off so we took the Bosch battery in and they said that was bad too. At $42 prorated (not bad), I installed the new battery and the light went off. Good right? 12.9vdc off/13.8vdc engine on...

Yesterday we took the vehicle to a friend-recommended auto shop. The SAME thing happened again! While checking the cooling system the alternator would not fully charge the battery and it eventually died. Upon getting it home I tested the battery terminals and it read 12.9vdc off/12.4vdc engine on.. another bad alternator one day after replacing it!

Though they can get one, I don't want another rebuild from the auto shop. They offer a "new one" but honestly I don't trust that it will be new unless I install it. What should be the next course of action? Do Mustangs require better parts than what I've settled for?

Thanks

(BTW, the second shop determined that the AC compressor core was bad. It just gets better all the time )

2001 Mustang Coupe 3.8L V6
45,000 miles

R.S.LOGAN

Sounds like you are getting crap alternators . Take it they checked and verified alternator was faulty before they replaced it FOC ?

jonwb

Actually I replaced both last year's and the one a few days ago (easy top-mount, 2 bolts, 2 electrical connections). Pep Boys tested the new Alt and said it was fine before I left with it.

Thinking about getting a Bosch alternator from NAPA?... I don't wanna get involved with Pep Boys anymore.

jonwb

Wife's boss said it could be the serpentine drive belt.. any mechanics here?

Bert

If the belt was the problem, you'd hear a lot of belt squeal.

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Bert

jonwb

Thanks Bert... actually had the squeal a year ago. It tapered off though after I used belt dressing and I didn't think anything of it. This morning, my neighbor (a Corvette club enthusiast) pushed down on it and thought it was loose.

Bert

If they're loose enough to cause poor charging, they'd make a LOT of noise unless they're wet with something slippery. I've never seen that. I doubt that the belt is the problem. If it's loose and/or worn, it should be replaced anyway. The charge rate should be checked with the engine running. The battery is checked with the engine off.

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Bert

jonwb

Well we have no charging at this point. Battery is fine at 12.8 but a load still sends it below 12.5.

Pep Boys said they would give me a new non-rebuilt ProStart Platinum alternator or give us our money back if we show a purchase from another dealer. They also suggested we change the 4-pin plug going to the alternator... probably a trip to Ford on that one.

I'm gonna change the Motorcraft belt just to rule it out... $25. Otherwise we may be looking at an electrical issue. That kinda money is gonna be hard to find

jonwb

Installed the belt... no change, though A LOT tighter. Car runs fine for one or two days but then the battery light comes on and a voltmeter test shows no charging to the battery.

What could be taking these alternators out?

R.S.LOGAN

Not a wiring to alternator fault ?