PLEASE SEND HELP RIGHT AWAY BEFORE I SEND THIS FORD TO THE JUNK PILE.........
I own a 1994 F-150 XLT, 4.9 straight 6, 5 speed manual, all the bells and whistles. It has 141,000 miles and runs great. BUT, I have put 5 alternators on since 1998 when I bought it with 89, 000 miles on it. They seem to last about one year. I usually notice the dash indicator start to jump from charge to discharge. Normally the needle will set about 3/4 on the dial. Never has run at exact neutral. When I am on a long trip, say more than 2 hours it happens. Before I installed the most recent one, I had been using after market alternators (external fan, internal regulator and recifier, 75A). These alternators had the back cover rotated so the regulator set within a couple of inches of the exhaust manifold. The one on there now(broken) is a ford factory rebuild (part number E8PZ-10346-CRM1) and the regulator sets somewhat further from the manifold. I could always smell something hot on long trips before the ford alternator was installed. Evidence proved the the regulator was being melted from the heat on the after market alternators. Since I hadn't smelled anything hot with the ford alternator, I assumed I had it licked. WRONG... Fourteen months (13,000 miles) after the ford alternator was installed, it broke too.
SO, my question is WHAT THE BLEEP is causing my regulator inside the alternator to burn out. There is no evidence of melting on the current one.
Yesterday, I checked the voltage at the battery: engine off: 12.8 VDC, engine on initially: 14.6 VDC abd the dash indicator set normal, after 10 minutes engine on: 11.6 VDC and the dash indicator set 1/4 scale and stayed there. I guess the regulator is bad again. I have replaced battery, positive battery cable, starter, fan belt, and have checked ground connections. There is no draw on the battery when the truck sets. I have left it for up to 3 weeks and the truck starts right up. Is there some kind of heat shield I could put between the exhaust manifold and the alternator?
Someone please help...........

 

Go get the NAPA Heavy Duty one and pay them the extra $15 for the replacment plan and don't worry about it.

Seriously, might be time to pay a stealership to diag the electrical system. Sounds like excess strain in the system somewhere is really eating up the alternator.

 

This reminds me of a problem I had with starters on my old 79, F-150. After about four starter in (2) years, I stopped at a local starter, alternator rebuilder and told him the problems I was having (this guy had personally rebuilt starters & alternators for about 30 years). After a few minutes he diagnoised my problem and sold me the part to cure the problem.

I have found that most times it is better to talk to a person that rebuilds these units--they can usually tell you first hand, why each unit fails.

Since local Guy cured my problem, I have swore my allegience to him--He has done all my starter & alternator work since and he does an excellant job at a very reasonable price.

P.S. My 1979 F-150 has the orginal alternator on it (164,000 miles).

 

Buy an alternator with a lifetime warrenty & don't worry about it.

 

Medic, you have obviously never broken down in the middle of nowhere. "Don't worry about it". What kind of comment is that, dumbass. If you don't have anything constructive to add, zip the hole.

 

Here's what I know now. I took some advise from you on-line folks and went to NAPA. They were knowledgeable and helpful. I asked for a heavy duty alternator for my truck and they carried a 80A and my 75A. The 80A would not fit my mounting bracket, so
I stayed with the 75A. The only difference between my old motorcraft and the one (Beck/Arnley rebuilt motorcraft) NAPA carried, was the alternator plug (not the regulator plug) was hard wired to the alternator. I had to cut my old plug from the harness and splice the new one in. Idiot proof really. What I found out was that Ford recommends replacing that plug every time you change alternators because the old worn plug can cause heat buildup and alternator failure. Beck/Arnley will not honor their lifetime warranty on the rebuild if the plug has not been spliced in.
So I put it on and works good now...... We'll see how long this one lasts. $152.70 at NAPA for part number 186-6221 with a lifetime warranty. I will say that this is the first alternator that I have installed that when I turn on the A/C, the radio, and headlights, the dash indicator drops and then recovers to normal.
I'll cross my fingers and wait.