Alternator failures--causes?

Good evening.

I have a 1998 Ford Explorer V6 with 172k miles. The original alternator failed in November, and I replaced it with a "premium" rebuilt alternator from NAPA. (The "premium" designation means that they install a new rectifier instead of a "good used" recitifier. I considered this an intelligence test.) This alternator failed a week ago. I returned it and they gave me another one.

What I am wondering is, could there be some other issue with the electricals that is causing alternators to fail? Certainly it is no surprise that the _original_ failed with nearly 170k miles on it, and it is also possible that the first rebuild was faulty. But now I am worried that a few thousand miles from now I will encounter yet another failed alternator, perhaps when I'm up in the mountains rather than a few blocks from home. I want to make sure that there is not something else wrong that is causing alternators to fail.

I checked the voltage drops from the BAT connection to the battery (+) terminal, and from the alternator case to the battery (-) terminal. The drops were

0.08v and 0.02v respectively. Those are acceptable I believe. Is there anything else I should be checking for?

Thanks

-Mark

Reply to
Mark G.
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How did the 'new' one fail?

What is the average charging output (use a clamp-on DC Ammeter?)

The concept that they 'use new rectifier' instead of a 'tested, good used one' is odd... First, you have no idea where that 'new' rectifier came from--and it probably came from china, where all crap like that comes from, while the OEM rectifier was probably a much higher quality unit.

Reply to
PeterD

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