Alternator...How long ...about are they good for?

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Probably, when the battery in my 1996 Contour had a dead cell, it apparently heated the alternator up enough to melt something--I have no idea what. (I didn't remove or install the alternator).

I found out it was a dead cell when the car wouldn't start and the battery read about 10V. Then I determined that after sitting (disconnected) for about 48 hours it would drop from 12.6V to about 10V, definitely a dead cell.

I had the old alternator rebuilt by a local shop that specializes in alternator and starter rebuilds, it's been about 60,000 miles with no problem.
 
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Assuming everything else in the electrical system (battery, cables, ect) is OK you should be able to get at least 10 years, 100K from them. Probably more. It can be a carp shoot though. Bearings and brushes especially. If the slip rings get messed up for any reason brush erosion will happen quickly.

Call me anal but I prefer rolling my own.




Never considered doing this as a part of the regular maintenance plan, but it sounds like a nice little project, especially if your alternator comes out easily.

It's a good idea, and I may have to consider trying this in a few years!
 
Jim, it has to be a labor of love and a desire to do things right or it isn't worth it. Plus you'll need some things. A rattle gun or other tool to remove the pulley nut for example.

A small lathe makes it easy to clean up the slip rings but one isn't needed. An insulation tester is nice unless you want to skip that test. It's not as if you're getting new or rewound stators and rotors in a rebuilt.

Do it right and it'll be as good as anything you can buy at a car store. (Maybe not as pretty though
wink.gif
Most auto store rebuilds are little more than strip and dips anyway.
 
333K miles and counting on my 88 528e's Bosch alternator. 2nd regulator/ brush pack. A 10$ after mkt part that takes 10 minutes to R+R. The delco alts that my Grand Wagoneer uses like kleenex are junk by comparison
 
Quickbeam..

I've got all the gear...even a 14" Clausing metal lathe. I may have to touch base with you when the time is right for a few pointers!
 
Don’t forget that alternator life greatly depends on the outside environment, in dusty conditions they will last less due to the higher wear on the brushes. The sand acts like a sand paper and bye bye alternator. If dust or contaminants get into the housing of the bearings that too will have an effect on overall life, but the greatest impact is the overall operating temperature. Alternators that do not receive much ventilation will overheat and die quickly, so if you double you current draw from say 10A to 20A your heat dissipation will quadruple if resistance is kept constant. Hence the reason why earlier posts mentioned that dead batteries will put a constant load on the alternator and if not cooled properly, the heat generated alone will kill it.
 
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Alternators that do not receive much ventilation will overheat and die quickly




The 2.3L Ford Fusion has some sort of air duct that goes from the front of the engine, just behind the radiator, to the alternator.

As best as I can determine it's there to provide airflow to the alternator.

The only bad part about this design is that it's the sort of part that some idiots won't re-install after they change the sparkplugs, since it must be removed to access them..and the car will "run fine" without it.

Much like battery insulators, which are another part that isn't often re-installed on the replacement battery.
 
What he said. Heat is a killer. The alternator on my 95 Ford van has about 190K miles and is still charging, but I think the bearings are getting dry. It's sometimes a little noisey at startup when cold, but I only drive this vehicle locally to take/pickup kids from school right now. If I were to go "out of town" I would replace it first!
 
If it has a Denso alternator it could be a good 15-20 years. I have seen a lot of Denso alternator's go 300,000 or more. The Mitsubishi type and Chrysler type alternators are also good units but not in the same class as the Denso units 7-10 years can easily be counted on for these units. Not to stir the anti-GM pot but Delco alternators are some of the worst ones made and have a very short life cycle and high failure rate! This is why your Dad was always worried. The only thing Delco's have going for them is their low cost for replacement.
 
I forgot to add I have no idea what you can expect from a motorcraft unit! I know I never had any problems with alternators ont he Ford I owned. I had problems with every other electrical part on the car includeing wire harnes, voltage regulators,fuse links and ignition modules but the alternator was rock solid. I even had a ton of car audio and 2 way radio gear in the car.
 
I think the 3G Motorcraft alternators (the ones with the internal cooling fan) are a lot better than the 2G ones (the ones with the external cooling fan). Both of those have an "internal" regulator.

Ford is now using something newer than the 3G, which dominated during the 90s. I think it might be the 6G.

GM used a Valeo alternator on the 2.2L Ecotec Malibu.
 
My '74 Volkswagen Super Beetle still has it's original Motorola alternator. They only used thsi particular alternator for a year and a half and mine has a sticker saying it was made in 12/73 on it and my car was made in January of '74.
 
Ben Boyle, That is probably the best alternator ever made. Motorola used to make the best electronics bar none especialy back then!!! I still like their componets over Japanese parts but they are pricey!
 
The shortest life ones are the "value" ones at Autozone. They are rebuilt skimping on everything. Individual diodes are unsoldered out and new ones soldered back in. A good rebuilder will replace the entire diode bridge.

The local rebuilder rebuilds the decent alternators, but the ________ alternators ("value" ones from Autozone) are put in a barrel and sold as scrap alternators for someone somewhere to rebuild.
 
I just replaced my daytona's Denso alternator(90amp) and it was the original I believe that came with the car. 183,000 miles and 14 years old. I swapped it for a same model ND from a junkyard I snagged for 20 bucks. It performs like factory, had it bench tested and it put out a perfect 14.4v and 100amps.
These NDs are tough critters.
 
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