2nd Gen Non-Engine/Transmission Is my alternator dieing?

[GAmes]

In the past when my alternator has quit, it did just that, it quit. The voltmeter would show battery voltage and the "gen" light would illuminate. For the last few days the needle has been going to the bottom of the white arc (whatever that voltage is) while at an idle, but comes up to 14 volts while driving. The gen light does not illuminate. This is a new one on me. Any ideas?

 

[jelag]

I've owned several trucks in the past and own the ones listed below now... . I've found that all high mileage trucks usually have brush failure first before something else goes wrong...

We've found that at some time, usually in the 300K mile range we take the alternator off, change the bearings, install new brushes and re-install. . With all the older Dodges, Fords, we've owned and sold with 500K miles on the clock I think each of them went to the auction with the factory alternator, with one bearing and brush change...

Hope this helps...

 

[Bob Cochran]

Mine started doing this as well but sometimes even at idle after awhile the voltage with go up where it belongs. In fact the voltage is slightly higher than it used to be!! This started after I had both batteries go dead; well almost dead and recharged them. I am not sure if it is the batteries they are close to 8 years old so it is time should pull them and load test I suppose. I have the tester so it is a matter of doing it. I will be following this post with a lot of interest.

In the past when my alternator has quit, it did just that, it quit. The voltmeter would show battery voltage and the "gen" light would illuminate. For the last few days the needle has been going to the bottom of the white arc (whatever that voltage is) while at an idle, but comes up to 14 volts while driving. The gen light does not illuminate. This is a new one on me. Any ideas?

 

[WilsonF]

As always I suggest having the OEM alt rebuilt @ a local shop. You never know what you are getting with a remanufactured. You can get rebuild kits with bearings and brushes from Geno's, mine took more than that, slip rings and a diode pack still cost less than a reman.

Floyd

 

[GAmes]

I have a rebuild, life time warranty. Since I travel having a warranty from a nationwide parts place makes more sense than attempting to rebuild one on the side of the road. I also have batteries that are less than a year old, although I recognize that a failure is possible. I'll disconnect them one at a time to see if there is a change.



Since two of you have mentioned rebuild I'm inferring that you think an alternator that puts out voltage like a generator would is failing. If disconnecting the batteries results in no change I'll go by an Auto Zone today and see if they will give me a new one based on my symptoms.

 

[PSpychalski]

Most diesels including ours have a generator. The field is energized after sufficiant current is built up in the rotor. The field is energized and amperage is sent to the batteries. You probably do not have a problem. With airplanes and boats with generators. a higher RPM is required to energize the field. Mine has done the same thing since is was new off the showroom. Once energized you will have full output till the truck is shut off. If voltage is dropping aff after field energized... may be regulator. Hope this helps.

 

[HBarlow]

Gary,

If I had to guess, I would guess brushes.

Your thinking about buying rebuilt alternators with a "lifetime warranty" from a national parts retailer sounds logical but, IMO, does not factor in the quality of the parts and labor in a rebuilt unit from the autoparts store. A warranty is not worth the frequent failures, inconvenience, and replacement labor.

I had high mileage alternators rebuilt on two Dodges by Amish craftsmen up in Indiana. The first time was because the alternator on my '01 failed one dark winter night as I returned to Wakarusa for another load. That alternator had been rebuilt not long before by a shop in Lubbock that was supposed to (but didn't) do good work. The Amish rebuild is still working fine to this day.

The second was on my '06 when it had 220k or so on the alternator and was still working fine. I had it rebuilt to avoid problems on the road. I sold it less than a year later so can't report on longevity of that one.

I swear by the attention to detail and pride in workmanship of the Amish.

 

[GAmes]

Most diesels including ours have a generator. The field is energized after sufficiant current is built up in the rotor. The field is energized and amperage is sent to the batteries. You probably do not have a problem. With airplanes and boats with generators. a higher RPM is required to energize the field. Mine has done the same thing since is was new off the showroom. Once energized you will have full output till the truck is shut off. If voltage is dropping aff after field energized... may be regulator. Hope this helps.

Actually it does not help. I know how a generator works, thus my reference to one. We have alternators, Dodge just chose to put a "gen" warning lt in the dash, probably for the non-mechanically inclined. I've owned this truck since new and it has never shown a difference in voltage compared to engine speed before. It has shown slight variences due to outside temps, which are compensated for by the temp sensor under one battery.

 

[mickeyblueyes]

Harvey could you share the name of the Amish shop so that we may be able to UPS a unit there to be overhauled instead of purchasing one made in Mexico or worse.

 

[HBarlow]

Harvey could you share the name of the Amish shop so that we may be able to UPS a unit there to be overhauled instead of purchasing one made in Mexico or worse.

Sure. I'll go out to my barn in a little while and dig through my business card holder in the truck console and see if I still have the guys business card. I think I do. If it's still there I'll post his name, address, etc.

The last one I used was in Shipshewanna, IN iirc.

 

[HBarlow]

I found it. I didn't find his business card in my truck, don't remember what I did with it. I quit transporting and left Indiana 2 1/2 years ago so must have purged my Indiana business cards.

It took a struggle on the internet but I found it.

Better-Built Starters and Alternators
65 S State Road 5
Shipshewana, IN 46565
(260) 768-3282

The owner and repairman is a young man, in his 30s, who is also a typical Amish farmer. He has a small shop built along the east side of the highway on State Highway 5 south of Shipshewana near Topeka, IN.

I pulled trailers for a year or two for a company with an office and terminal in Topeka and lived up in that area. I stopped by one day and interviewed the shop owner. I liked his attitude and asked him to order the parts for my Nippodensa alternator while I was on the road. A few weeks later I stopped by and he had the parts. He pulled the alternator and overhauled it while I watched and waited. He used quality brand name parts and did careful work. His price was very modest.

I promise you that you will be pleased with his work. Tell him he overhauled an alternator in a new white Dodge dually for a transporter from Texas about three years ago and I recommended him.

 

[HBarlow]

After struggling to find the Amish alternator repairman on the internet I found his business card.

Better-Bilt Electrical
Starters, Alternators, & Generators
Exchange or Rebuild Your Unit
From 6 volt to 64 volt We Do Them All

Dean O. Graber
65 S SR 5, Shipshewana, IN 46565
(260) 768-3282

 

[DieselDoghouse]

WOAH! I'm not flaming anyone and not looking for scorch marks but reference PSpychalski post above, NO, NO, NO. I'm looking at the shop manual now and our (2nd generation) trucks most definitely have ALTERNATORS, not generators- 3 phase alternators rectified to DC. Picking a fight or important?? Important - I believe Chrysler was one of the first car companies to discover: generators vary their output CURRENT with (engine) speed, alternators vary their output FREQUENCY with speed - but largely we don't care after it passed through 6 healthy diodes being converted to a (fairly) pure DC. The only major influence on charging current is excitation of the rotor winding - under control of the PCM - AND those 6 healthy diodes?? Every time (almost) on any vehicle with an alternator when I've experienced what you are describing a diode has pooped out (they do) and I've limped home with a 2/3 phase alternator—crappy output at idle but some courage at higher engine speeds. If you don't have someone competent to test the unit, replace it or send it to a reliable alternator shop for rebuild. the technicals of why are involved or boring and I've posted elsewhere here. But trust me - I would be very suspicious this IS the cause.

 

[CCiatteo]

I can't say for sure, but my alternator died a slow death as described by the OP. First it was slow to come up to full charge on start up. I thought maybe it was grid heaters or something acting up intermittently. I checked the batteries, the grid heaters etc. Then the alternator would drop out when stopped at a light or at idle, but come back after getting underway. Until ultimately it was toast.

If I was you GAMES, I'd pull it and have it tested and replaced under warranty, if possible. Sounds like its on its way out.

Chris

 

[Bob Cochran]

Finally got around to checking my truck systems with the following results.

1) Each battery tested good when load tested as well as standing voltage.

2) Alternator putting out 14. 4 volts at idle only thing bothered me was voltage jumping between 14. 4 and 14. 6 at 1200 rpm. Steady at idle14. 4 but jumping at higher RPM. When grid heaters operating the voltage dropped to 13. 6 still in the green. Not sure one or both cycling.

3) Alternator was putting out 10 amps running at 1200 rpm right after start dropped to 5 amps short time later and at idle around 2. 5 amps I don't have enough resolution to be more exact. I forgot to look at amps when grid heater cycling. The amps was jumping around like the voltage not unexpected.

I guess will have to wait and see if things get worse before doing anything everything in the green. Just not operating as it was before. Oh before you ask the jumping I noted was after the grid heaters stopped cycling. Next project mechanical gauge check of fuel pressure from my Air Dog as mine might be high like others have said.

 

[GAmes]

I didn't have access to the internet for the last few days. Auto Zone tested and replaced my alternator. I've put about 2000 miles on it, night driving with a couple different trailers and it works as it shouldOo.