# Alternator Keeps dying



## fliv (Feb 14, 2007)

I have a 2wd 97 Nissan pickup. Before Christmas I replaced the alternator (AutoZone said it was bad). The truck ran for about a week and then died. I had my repair shop fix it. It ran for another week and then died. They fixed it a third time but I am afraid to pick it up. To me it is obvious that the problem is not the alternator. What could be causing my alternator to die on me? The repair shop does not seem to be much help anymore. The alternators I put in were remanufactured. The battery is new.

Thanks.


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## golfer (Aug 21, 2006)

They could be just crappy , cheap rebuilt units.
A bad battery will also destroy alternators but the repair shop tested that ... right??


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## nissanmadness (Sep 18, 2006)

fliv said:


> I have a 2wd 97 Nissan pickup. Before Christmas I replaced the alternator (AutoZone said it was bad). The truck ran for about a week and then died. I had my repair shop fix it. It ran for another week and then died. They fixed it a third time but I am afraid to pick it up. To me it is obvious that the problem is not the alternator. What could be causing my alternator to die on me? The repair shop does not seem to be much help anymore. The alternators I put in were remanufactured. The battery is new.
> 
> Thanks.


I once replaced 3 alternators on a friends car. These came from Advanced Auto. Just because they were rebuilt, doesn't mean they were done right. Get one from a reputable elec shop. AutoZone should refund you your money.


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## Fred S (Aug 26, 2006)

When I see three "bad" alternators in a row, I come to the conclusion that it's probably not the alternator. Yeah, it can be thre bad ones in a row, but it's not likely.

I'd get the alternators tested off of the car. AutoZone can do that. If they test good on a bench tester then you know the problem is your wiring or battery.


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## nissanmadness (Sep 18, 2006)

Fred S said:


> When I see three "bad" alternators in a row, I come to the conclusion that it's probably not the alternator. Yeah, it can be thre bad ones in a row, but it's not likely.
> 
> I'd get the alternators tested off of the car. AutoZone can do that. If they test good on a bench tester then you know the problem is your wiring or battery.


IF you were a mechanic, your conclusion would have been wrong. The stator coil failed in three different alternators in two weeks time. You probably would have done some futile diagnostics costing the customer more money and nothing to show for it. I just stated a situation that was factual. I would never purchase any elec item from AutoZone or any other store in that line. Though the customer bought it, I installed it. Many of those people behind the counter are pretty much lacking in experience and know how. However, if it floats YOUR boat, to deal with them, then so be it.


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## Fred S (Aug 26, 2006)

nissanmadness said:


> IF you were a mechanic, your conclusion would have been wrong. The stator coil failed in three different alternators in two weeks time. You probably would have done some futile diagnostics costing the customer more money and nothing to show for it..


I don't know why my post set you off. I don't much care either. I was posting in response to fliv.

I stand by my statement that three failures in a row is pretty unlikely.
I also stand by my statement that bench testing an alternator is a good way to determine if the failure is the alternator or the vehicle's wiring. For those lacking the tools or ability, AZ is a good way to do this.

I wasn't questioning your story. I was trying to help fliv out. If you have a problem with that, too bad.

Fred


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## golfer (Aug 21, 2006)

Actually a dynamic test in the vehicle is the best way to test the electrical system including starters and alternators.

Bench testing ( static ) is the easiest for DIY .


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## Fred S (Aug 26, 2006)

golfer said:


> Actually a dynamic test in the vehicle is the best way to test the electrical system including starters and alternators.


You are correct that a dynamic test (rotor spinning) is better. A rotor can show perfect continuity while idle but fail when in use. What happens is that the centripetal acceleration pulls the wiring apart creating an open circuit. It's an uncommon failure since it requires a bad job of sealing the windings when the rotor was built.

By bench test, I'm referring to a benchtop machine that spins the alternator. The advantage here is that the car's wiring is not a factor.

Fred


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## nissanmadness (Sep 18, 2006)

Fred S said:


> I don't know why my post set you off. I don't much care either. I was posting in response to fliv.
> 
> I stand by my statement that three failures in a row is pretty unlikely.
> I also stand by my statement that bench testing an alternator is a good way to determine if the failure is the alternator or the vehicle's wiring. For those lacking the tools or ability, AZ is a good way to do this.
> ...


It sure sounded like you were questioning my story. Your statement that three failures is pretty unlikely, is what? Cheap parts + cheap labor =cheap product. What don't you understand. Get over yourself, alright.


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## Fred S (Aug 26, 2006)

nissanmadness said:


> It sure sounded like you were questioning my story.


Well, I wasn't.



> Your statement that three failures is pretty unlikely, is what?


A fact. What are the odds of a bad alternator? Pretty good. What are the odds of two bad alternators? Not so good. What are the odds of three bad alterators? Even less.

Assume that a reman alternator has a 1% chance of being bad.
The odds of three bad ones in a row are 0.01 x 0.01 x0.01 = 0.000001
That's 0.0001%
Pretty unlikely, yes?

It's simple math. Ask anyone who has ever gambled or paid attention in school.

The point which you seem to be missing is that when a failure happens, a part is replaced, and the failure happens again, it's time to open your mind to the possibility that something else may be going on. Possibly there is another bad part that causes the replaced part to fail. Possibly the part that was replaced was never the problem. You need to consider this.

This ability to diagnose and locate the source of the problem is what seperates mechanics from parts replacers.



> Cheap parts + cheap labor =cheap product. What don't you understand.


I don't understand the popularity of boy bands.
I don't understand how to make tiramisu.



> Get over yourself, alright.


You're the one who chose to be insulting after I posted attempting to help out.
Get thee over thine own dumb self.

Either way, I'm done talking to you.

Fred


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## nissanmadness (Sep 18, 2006)

Fred S said:


> Well, I wasn't.
> 
> 
> 
> ...


Just because YOU put faith in cheap parts is no reason the rest of us have to. My guess is you'll always be a parts changer. It sounds like what you are due to your lack of reasoning,understanding of the subject and weak attempt at trying to sound intelligent. We hope someday they find a cure for ignorance such as your own, of which you are a fine example. One word of advice, don't sit down too hard, or you'll break your neck.


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## 88pathoffroad (Jun 6, 2004)

Nissanmadness, cool the hell off and eat a sandwich or something. People here are NOT out to get you. If you can't find something helpful to post, just try not to post anything.


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## 88pathoffroad (Jun 6, 2004)

Fred S said:


> Well, I wasn't.
> 
> A fact. What are the odds of a bad alternator? Pretty good. What are the odds of two bad alternators? Not so good. What are the odds of three bad alterators? Even less.
> 
> ...


Exactly. I ran into a very strange problem last week on my brother's S-10 Blazer. Electric fuel pump died, so I install a new one. New one dies within a few seconds of engine running. Return, exchange, get a third pump. It dies after a few minutes of running. Electric motor just simply fails in each case. Hooking it up directly to the battery shows no function at all after they fail.

Three bad fuel pumps, right?

Wrong. The alternator was putting out AC voltage because the diodes died. AC kills some types of negative-ground-only electric motors, just like the fuel pumps I was putting in.

See how that works sometimes?


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## nissanmadness (Sep 18, 2006)

88pathoffroad said:


> Nissanmadness, cool the hell off and eat a sandwich or something. People here are NOT out to get you. If you can't find something helpful to post, just try not to post anything.


No problem 88, but i remember you and TonkaDriver going at it over a spacer too. The fourth alternator I installed is still working. So tell me why I would look anywhere else when I already knew where the problem was. See how that works sometimes! I never said anyone was out to get me. But when an individual tries to justify his statement using laws of averages, percentages and a cockamamie equation, I gotta comeback. Have a nice day!


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## airdevil85 (Oct 20, 2007)

I have the same problem, I have a 97 hb with the 4 cyl... The truck has 77,000K it is on alternator number 4 in less than a year


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## ff14007 (Aug 26, 2007)

i used to work at autozone for about 2 yrs. i saw some things like starters, alternators, brake master cylinders, calipers, and such bad in the box on the shelf. it was just put up from recieving our truck for the week. so i can understand that things can go bad very fast due to the rebuilder screwing up on the unit. i have seen used parts in the "new" boxes more than once. why do you think i left? i couldnt knowingly sell those parts to people. god forbid something like a master cylinder goes bad a week after it was replaced. so all i can say is they sell what they get.


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## airdevil85 (Oct 20, 2007)

that sucks


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