I have a 1999 F 150, 4.2 L V-6, without air conditioning, on which I had to replace the alternator about a month ago. The OEM one had a cracked case putting the shaft out of line and the pulley stopped turning. Yesterday, as I was driving along a local Interstate, my radio quit, the dash instruments shut down soon thereafter and about 5 miles later the engine quit.
After coming to a stop I looked under the hood and nothing appeared amiss. No signs of engine over heating. The battery seemed OK. The wires to the alternator were secure and in place and belt tension was about as I remember it after installing this rebuilt alternator.
When I got the truck back home I put the battery on a charger for 5 hours (at 2 amps) and it started right up. There was no loss of radio stations, etc. as when the battery has been disconnected. The alternator was being turned by the belt and was not making any unusual noise. However both an electrical tester I have and the dash instruments indicated the alternator is not charging.
No blown fuses. The alternator is securely bolted to the engine and there is power to it from the battery. I checked the alternator electrical connections continuity as far back as I could and didn't find any faults. Is this alternator dead or is there some other possible problem? Any suggestions would be appreciated.
Thanks,
Mike

 

Bad re-built alternators are very, very common.
New are of course new. Less problems with those.
Always ask what you are buying. There are Re-built, as above, re-manufactured, meaning everything is replaced except the housing and new is new. The best bet for the money is re-manufactured, not re-built. If a bad alternator might just needed new brushes, they get replaced cleaned and sold as re-built. In re-built the only thing replaced is what made them go bad.

You probably just got a bad one.

Check your voltage while engine running with the lights on pulling a small load. It should read 13.8v to 14.8v...anything else and you have a bad alternator. Rev the engine to higher than idle...2500rpm is more than enough. It still should read 13.8v to 14.8v.

good luck...

see this link too...
https://www.f150online.com/forums/sh...d.php?t=210335

 

Yeah, I agree.

 

Thanks for the reply. It check out OK when I installed it and ran a little over 1000 miles THEN failed. That is the confusing part.

 

My alternator went up about 5 years ago. I got a new one from Napa with a lifetime warrantee and they have replaced it twice since then at no charge.
I have electric fans, electric trans cooler and tow quite frequently so I probably put a heavy load on the alternator. Napa has never given me a problem with the replacement.
You need to find a reputable dealer first then get one with a good warrantee.

 

Can't argue with your logic but I haven't talked to the parts dealer yet (Carquest). The two failures are unrelated to each other. The first was a cracked alternator case which caused the armature to go out of line and the pulley would no longer turn. It came from the factory with at least one of the cracks. This recent failure is a mystery so far.
What was the extra cost on the Napa warranty?

 

There was no x-tra cost, part of the price for the Napa alt.

 

I talked to Carquest yesterday and I have a two year warranty on the alternator which they replaced. That cleared up the charging problem but caused a new one. When I start the truck up it get quite a squeal from the belt which was new 6 weeks ago.
Best I can tell it is caused by the alternator. It doesn't appear askew and it seems with 3 bolts lining it up correctly shouldn't be a problem. The squeal goes away within 30 seconds or so but the same thing occurs every time I start the truck. The alternator was quite warm to the touch (didn't burn my hand but I wouldn't want to leave it there very long) after driving and I only went about a half mile. Thoughts and suggestions would be appreciated.
Mike

 

sounds like your autoparts store is replacing u with faulty merchandice.. get your money back and go to napa or another parts dealer.

 

Thanks for your reply. I've been going to Carquest because they are closest, about 5 miles vs. 25 for any others. The guys here seem to like NAPA a lot but I'm not so sure that there is much difference between the auto parts chains. I know some people in the industry and I'll see what their opinion is. Maybe you're right.
I checked the alternator with a level to the nearest other pulley (all 4 edges of the pulleys touching the straight edge) and found it didn't line up quite right (about .025 to .030 by inserting something between level and pulley edge). I realigned alternator as much as I could (got it down to about .010 to .015) and changed belts. Went for a short test drive, no problems. No more squeaking and the alternator didn't seem overly hot afterward.

 

good gladd to hear ur problem is fixed