Replaced the alternator 4 times in 2 years

Has anybody ever looed at the alternators to decide what the failure was?

They are really simple device, actually. There is a stator, a commutator, magnets and the transfer rings. Also, this probably has an internal regulator.

My best GUESS is the regulator is crapping out. This can be caused by too much of a load, in which case you'll have to look elsewhere; a draw on the current, the charging system, starter, on and on...

If the windings are burning, the brushes are wearing out rapidly, the bearings are grinding, or something else, then there is something working on the alternator. My guess here would be you're overtightening the belt.

Are you using GOOD alternators? When I was working at a parts store we dropped the cheapest aftermarket reman. unit because they were CRAP! I've seen them blow in a WEEK!

The other things I would check would be loose or disconnected connections, and especially a loose ground somewhere. Grounds can cause WEIRD problems!

OK, my first question would have been if it's an ND or a Delco-ReamMe. I was changing alternators on the Corolla a lot until I got an ND alternator. Still going . . . .

Charles of Kankakee

I never owned a NUMMI made piece od sh...er, car, so All my Yota's have Densos...

I have only replaced ONE alternator. You can order the brushes from any parts store and solder them in (or screw them in, if so equipped), likewise for the regulator. Cheap!

I had a similar problem with my '85 Toyota Van, but perhaps not as bad - - it went through a couple of alternators while in each of their warranty periods. After replacing the last one, the Arco Mechanic said there's a lot of oil on the alternator, and sure enough, there was a loose power steering connection that dripped oil on it. Now it's dry and running fine.

For most people, replacing brushes or the regulator would equate to an alternator replacement since fixing *anything* is out of vogue today. Also, diodes don't wear out so regulator replacement can always be traced to manufacturing defects.

Well, since the battery is the load of the alternator I would have it checked.

Diodes don't wear out?

I could tell you a couple stories to refute *that* statement!

Good thing I was wearing my Safety Glasses *that* day!

Start by looking at the battery. Have you ever replaced it? Have you ever taken a fully charged battery and checked the draw on the system with nothing at all turned on? A shorted cell in the batery would probably put enough strain on a cheap alternator to kill it. A short in the system big enough to draw significant current all the time may well do the same thing. My experience with remanufactured alternators on a couple of vehicles was basically plan on doing the job twice because the first one will be crap. I also had something short out on our old suburban once and draw significant current, but not enough to drain the battery most of the time. I found it when I was digging through the fuse box and found a self-resetting circuit breaker hot enough that I had to use pliers to pull it.

I'm changing every year. 93 Prizm (Corolla)

Second time it was under warranty so mechanic replaced but claimed there must be something else becuase it is not normal (doh!). They checked and they told me they found a short. Third time, failed again and they claimed they found a failed electrical cable (every time I was paying for those extra repairs). Last time I took to another mechanic, told the history, he replaced and he claimed it wouldn't fail. I heard that before, but I have another 8 months to prove him wrong.

I think I should consider brand name and other stuff people mentioned here. Thanks fellas.

Good luck! Let us know what happens!

you could hook up a amp meter and measure the current flowing out the battery, if there is a short you should see a good amount of current flowing, then start removing fuses, you will see a big drop in current when you pull the fuse on the system thats causing the short. If that system isn't needed then your done! Otherwise you need to track it down some more.

Removing the battery cable is not a bad option, I've done that for a few years on a old second car I had and rarely used, I could never find the short.

Thanks for the help!!! Seraching online I found a Vector Portable 12-Volt LCD Voltage Meter. This Portable Voltage Meter plugs into your vehicle's cigarette lighter and measures the voltage output of your car. Could I use this type of device to measure the current flow as you suggested?

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bungalow snipped-for-privacy@yahoo.com wrote:

No it isn't...

Easy...when you get home and take a battery lead off (negative lead I'd suggest) put a DC ammeter set to a fairly low scale, maybe 0 to 300 mA, between that lead and the post that you took it off of.

Note when you connect the lead which way the meter moves, if it moves 'downscale' then swap the leads...let us know what kind of a reading you get...make sure that all the lights are out and the key is turned off...make sure that there isn't an 'underhood' light on...

Yes, this can certainly happen...all cars now-a-days will have a little draw for things like the computers, clock, and radio backup etc...and some batteries are so poor that they can't handle even this small draw, so you could have one of those...but the amount of draw will tell us, so let us know...

No, this is a voltmeter...it doesn't mention having a 'current measuring capability', plus it's 32 bucks...plus you CANNOT do this check at the cigarette lighter socket...hell, ask your mechanic if you can't borrow his VOM (or let him measure the current for you)...

Make damned sure that you don't put someone's meter set to 'current' ACROSS your battery...you'll likely blow up his meter!...

Stupid question: Is your normal driveway parking place level?

If you are parking on a severe incline, you can be activating a trunk or hood light with a tilt switch and not know it. That will run a weak battery down overnight (and a good battery in a few days) and you'll NEVER find it...

Other than that, you (or your mechanic) will have to get a digital voltmeter with a DC milliamps current function and see if you have a parasitic draw somewhere, either a short circuit, or bad diodes in an alternator, or an accessory that isn't turning off as it should.

Realize it's normal to see 5 to 10 milliamps of draw (.0005 to .001 amp - I think I have the decimal point in the right place, point being it's tiny) for the computer memory circuits and the clock, and toward the high end if you have an anti-theft system or remote unlocking receiver. A good battery can supply that much current for a few weeks easily, but more than that is trouble.

You won't even see the needle move on a small draw like that with an analog gauge you can afford - and a good analog gauge that will indicate into the milliamps range is really easy to blow up by running an overload through it. Just open the door. You either need a good digital voltmeter to check this, or a fused analog meter, or a series resistance to protect the meter, that's the time to let a mechanic that knows these tricks mess with it.

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No but this $7 DVM will work, use the DC Current reading, you need to remove one cable from the battery and then connect one lead of the DVM to the cable you removed, then connect the other lead of the DVM to the disconnected battery termimal (the terminal you just removed the cable from). The meter will then be reading the amount of current flowing out of the battery. Then you can start removing fuses while watching the meter.