What's Eating my Alternators?

So I had to replace my Avalon’s alternator back in October @~ 150k miles.
I just had to replace THAT one! It’s been what? 8 months and ~10k miles? Is it just a bad factory product or could there be something killing them? How would I check?
I have already checked the new one and get 13.6V(+/-).
I checked the voltage drop between both +/- and those are good.
Just wanting to cover my bases.

Covering your bases would include the year of the vehicle?


Could be, all stock equipment ?
No after market HID headlights, high powered amplifier ?

How about budget repair parts? Low cost replacement parts are designed for people that are going to hang a For Sale sign on the car the day after replacing the alternator.

Pep Boys specializes in selling these kinds of parts. They don’t say they do… but they do.

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Most likely defective teplacement part. Others, belt or pully, something drawing more current than it should. Most owner caused are giving and getting jump starts.


Bad luck is certainly a possibility. The last alternator in my Corolla lasted maybe a year and a half.

Depending on the year (you didn’t say) OEM may not be available. If you still have the original core, one solution would be to take it to an auto electric shop, have new brushes and bearings installed, and if your alternator windings are good, you should be all set. BTW: Did you replace the voltage regulator?

I’ve had this done for aircraft alternators (in my case, made by Chrysler) by an FAA approved repair station.

Like others have said: It is quite possible that the replacement alternator was no good.

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If there is a wire connection problem on the battery sense wire that would make the regulator “think” that the charge on the battery is low and make the alternator over work. See if the alternator case gets hot after a short drive. That could be a sign there is a problem.

How about an iffy battery or a poor connection between the alternator and battery terminal?


During the summer months the load from the radiator fans, A/C clutch and blower motor, fuel pump, ignition system, DRL or worse the headlights will require 30 to 40 amps while running. This is a great continuous load for a cheap alternator. A remanufactured alternator from Toyota is $420, this is a part that you can rely on for ten years.

Thank you for all the replies!
It is an 08 Avalon.

We had to replace the alternator on our 2012 Honda Odyssey earlier this year. A cheap one was around $450 (with labor), and OEM Honda was around $600, I think it was. We went for the OEM. The relatively small price difference but increased quality made sense to me.

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The most economical choice is to have the factory original one repaired at an auto electric shop. That means you can’t drive that car while you wait for the repair to be done and to reinstall it.

I looked at a Toyota website, and a factory reman alternator for a 2008 is no longer available. It’s been replaced by another part number, but I can’t verify whether or not it would fit yours.

Best bet would be to get it to an auto electric shop like shanonia posted. A lot cheaper than the $348 Toyota would want, even if it does fit your car. :


Its the first time I’ve heard that analogy & its a great point.I can indeed agree that alternators, starters & especially efi sensors are very notorious for having a super short lifespan.With companies like RockAuto being in business,dealer brand parts are very affordable,so if you’ve got the time to wait a few days for shipping,its imperative to buy dealer parts/sensors.Even if a generic or parts store brand sensor has a lifetime warranty,
the time it takes to remove & replace that part will likely get old once you have to start replacing it over & over.

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A used factory original alternator from an auto recycler can be a very good bet, too - better than a lot of the aftermarket electrical stuff.

Make sure the primary & secondary grounds are tight & corrosion free because a bad ground at either will cause the alternator to max out.Primary is between the neg battery post and the engine & the secondary is between the engine & chassis. Sometimes when the secondary ground is loose or disconnected,
it will cause the temp gauge to increase as you turn electrical accessories on like the ac,blower motor,headlights,etc.