i have a 88 f250 5.8 and ive been replacing the alternator with napa reman units. they havent been lastin a year im on my third one. they have been replacing them under warranty but its gettin to be a pain in the a$$. i think its the regulator.it will spike the volt guage to the positive side and make the lights super bright. im afraid its going to cook somethin electrical one of these times. any suggestions?

 

Did you replace the Rectifier & Regulator Connecters ? Have a look at them , If they show any signs of melting , replace them . Are you using Dielectric Grease on those connecters ? Whats the condition of the battery & battery cables ?

 

i replaced all the connectors the first time i had a problem because the alternator actually caught fire! also all battery cables are new.and the battery. the regulator is on the alternator so that gets changed when i change the alternator

 

Normally , Napa sells fairly decent parts . You seem to have covered all the obvious , Try A Ford alternator . Im not a big fan of aftermarket parts simply because a lot of it regardless of warranty is junk . A lifetime warranty is useless if you spend a lifetime replacing the part . My original Ford alternator lasted 10 yrs , it was replaced last Jan with the same from Ford , Its still doing its job with no problems .

 

I have used NAPA replacement/Rebuilt Alts many times in the past. I would never get past two years with a NAPA alt on my 92' F-250. I would get the hottest amp alt available which was a 90 amp output at the time. I just had to replace the alt last month and the NAPA replacement crapped out two weeks ago. They replaced it and the replacement just started to act up. No amperage! I will probably have to replace it again. Long story short, I am not happy with the latest NAPA alt manufacturer. They seem to change manufacturers every couple of years or so. Hope you get squared away. Jake.

 

I have an 88 F250 with a 300/6. When my alt took a dump I started calling around and found out that there are like four different types for that particular year of truck. Three of them were 90 amp and one was lower. I couldn't tell you the difference because nobody seemed to know, but I matched the numbers up and have had two years good luck out of a NAPA gold.

 

my alternator is a 75amp. i use this truck to plow snow so i really cant afford breakdowns. i try to check everything over well and then this happens. my plow is all hydraulic so thats not stressin it. just a pain in the butt with this alternator stuff.

 

If you want look in the back of a 4x4 mag, they have Mean Green Alternators. You can get them to crank up to 140 amps. These extra amps would be nice using the plow, and defroster and radio and lights and whatever else you may be running.

CJ

 

Yep! Just replaced it again! It's like changing your socks. Becomes second hand knowledge after doing three times in one month. So far so good. Seems to be running fine now. One thing to take into consideration is that when changing your alt you should check the complete wire pigtail from the alt to the battery. The pigtail on my truck is the heavier built one but the end that goes to the fulltime Pos hot side of the fenderwall solinoid was looking a little worn and weak. It is very possible that this may have been part of my problem but in past practice, I have seen worse not play that part. My NAPA dealer mentioned that there have been problems in the past but nothing too prevalent with there latest brand of alt that they have carried. Something to think about. Good luck. Jake.

 

WOW!! Topic for Topic:
Alternators burning out, voltage spiking on guage: Cause, rectifier unit it not soldered to stator wiring inside alternator, Does Ford do this, NO they do not, but this causes another problem for longevity, they just specify how tight the connection needs to be, we solder to be sure, Second, rectifier unit is not of equivalent Voltage saturation as O.E.M., which is more important than first, Diode assemblies come in different stength ratings, they blow most of the time when they don't meet O.E.M. specs. Rebuilt internal components such as the rotor when they are rebuilt, they usually turn down the rotor with a sanding machine trimming of metal, note of caution, 1 one thousand of an inch of metal off the rotor = 9 amps at an idle, this unit only does when new 30-35 amps at an idle, air gap between rotor and stator is critical of these units on function ability. O.E.M. has to meet this spec. not saying the aftermarket does not, you need to make sure, of the components that they are using, You are to trust them that there suppliers are using the top quality parts, what do you think, read on.

Wiring burned up at alternator, Cause: wiring connection loose in connector at Alternator or inside at the Stator to Rectifier connection, Problem is that most of these units are 75 amp units on a 1988 F-150. There is 2 wires which are black and orange that feed all the power out of the alternator to the electrics of the truck, divide 75 by two and you come up with 37 amps out each leg of a push on terminal, alot of power in push on connectors for continuous use, or inside the Alternator ther is three connections at the Stator to Diode connection, if the rebuilder does not replace the Stator, they are reusing the connections which are already loose from heating up and cooling down from 70,000 miles of use. Do you see the problem Ford left you with, They noticed it, they don't even rebuild this unit any more.

Dielectric Grease, Helps to keep out moisture in the connector, it does not help in transfering of power through the connection, just helps to keep moisture out to keep the connection clean.

Warranty, I'm not afraid to use aftermarket parts, I just need to know if they meet O.E.M. Specs. before I put them on a Customers vehicle or my own. The word warranty is a selling catch, they know it and most people that buy there product know it to.

Batteries: O.E.M. has designed this vehicle to run on a 65- series battery not a 70 or 26 or 34/78 or 34. Ford vehicle do alot of spiking in the system and need to take it into consideration, the battery not only starts your truck, but also is a big capacitor to take up the surges or spikes in the electrical system. O.E.M. spec. comes in to play here again.

1988 F-150 has 1 style alternator, it is called the 2G alternator, second generation, external fan, internal regulator, comes in 60, 65, 75 amp units, in 1990 they came out with the 3G unit, third generation, internal fan, internal regulator, 90 and 130 amp unit, not interchangable between units, you can install the 3G 90 amp inplace of the 2G with a simple wire change and upgrade. Diesel and other higher applications can take you to a Mitsubishi 215 amp unit factory installed. There is a 70,90, large frame alternator that was used on F series trucks, Mainly Diesel. Straight across and 2:00 mounting ear main frames.

The next time you go to an aftermarket parts supplier, ask them if there components that you are going to purchase from them meet or exceed the factory built vehicle specifications.
If not, you know what to do, if yes, ask to see it in writing, if they laugh at you, here again you know what to do.

Maybe I am going in to deep here, sorry if I am, but it appears to be needed and questions are being asked or received. All of this was taken into consideration when the O.E.M. designed your vehicle, Don't reinvent the Vehicle, just make sure you are using the quality equivalent parts for your repair. It makes your vehicle more reliable on the road. Electric1

 

Nice posting Electric1. You have given us some very useful information. Some of which I have heard of but the majority of it is new to me. Thanks. Jake.