SOLVED! Alternator not charging

[joe mama]

Do these alternators go intermittent when they're bad?

My 2003 4.2L TB is on the original alternator, nearly 200k. No funny noises, and RPMs don't seem to matter. The other day the voltage went to 12 (and a bit lower) while driving. Took it home and waited a couple days. Magically it fixed itself and was back to 14V....for a while, then back to 12V. That happened again today, started at 14V, drove 30 minutes and then it went back to 12V.

 

[Ilikemy3s]

YEs they do act that way. Mine started doing that a little bit later than yours. Had to keep wacking it with a hammer and pipe (while it was running) to get it to charge again. Got worse over time. Best to just replace it.

 

[Mooseman]

Yes agreed, it's on its last legs at that mileage. Can also have it tested at a parts store.

 

[joe mama]

Thanks for the feedback! New AC Delco unit from Rock Auto installed, seems fine now. 197,800 miles is pretty good for the original. Due to the mileage, and because I was in there anayways, I also changed out the idler pulley, tensioner, and serpentine belt.