two failed alternators
Details on Truck:
1992 Ranger, 4-cylinder, 2-wheel drive, 250,000 miles, oil leak likely
I got in my truck on Christmas eve after work and it wouldn't start on it's own. Had to get it jumped. co-worker said to check out the alternator, so I took it out and had it tested at an auto parts store. It failed the test and I purchased a refurbished replacement. Truck ran fine for a week.
New Year's eve, I picked up my kid from daycare and I had to get a jump again. When I was idling the engine, RPM's showed 4,500 and when I revved the engine, it would go down to 1500, like it was reversed somehow. ??? Got the truck on the road and drove about a mile and the engine died going 45 mph (after I flashed my brights at someone who pulled out in front of me). At this point, the headlights and hazards did not work, but the dome light was working somehow.
Tow truck driver said the alternator probably failed again, so I took it out and had it tested again.... failed.
I tried to fire it up last night with the replacement, replacement alternator and it wouldn't start without a jump. Once I jumped it, it ran a little rough and when I flashed the brights, the engine died.
I'm running out of ideas at this point. The battery shows 12.5 volts at rest and when the engine was running, it showed 13.5 volts. I suppose I could have really bad luck and this is the third bad alternator, but I doubt it. The guy at autozone said that the oil leak could be causing the alternator to fail, but I think he's full of it. What else could I check?