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Discussion Starter #1
I'm on my 3rd alternator in my 02 4Runner SR5 2WD w/ 240K on the odo. Each alternator failed within 12 months. 1 each from O'Reillys, Autozone, and then the local Toyota dealer. All were manufactured units.
Is the ANY reliable alternator brand out there that someone can recommend?
Or is there another part that might be causing this issue? Other than alternator issues, the vehicle has been bullet proof!
 

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short-throw dipstick
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I use the Denso remans (which may be what your dealer is slinging). Never had any problems, about to put another in an '00 ES300 today.

Goes without saying but there may be some other issue causing this
 

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1995 Toyota Corolla
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The original Delco alternator in my Corolla failed after 22 years and 260k. The Denso-based Carquest remanufactured unit that replaced it is running well 2 years and counting.


Do your remanufactured units have lifetime warranties? If they do, you could take back one of the failed ones and keep replacing them until you get a good one. Was the belt correctly tensioned?
 

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Discussion Starter #4
The original Delco alternator in my Corolla failed after 22 years and 260k. The Denso-based Carquest remanufactured unit that replaced it is running well 2 years and counting.


Do your remanufactured units have lifetime warranties? If they do, you could take back one of the failed ones and keep replacing them until you get a good one. Was the belt correctly tensioned?
Thanks for your reply! They all had 12 month warranties, and I wouldn't mind swapping them repeatedly if it was my car, but it's my daughter's and she's 800 miles away. The last one was installed by the Toyo dealer and should have been tensioned, etc., correctly.
 

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1995 Toyota Corolla
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Thanks for your reply! They all had 12 month warranties, and I wouldn't mind swapping them repeatedly if it was my car, but it's my daughter's and she's 800 miles away. The last one was installed by the Toyo dealer and should have been tensioned, etc., correctly.

I understand your need for a stable solution then. Is the battery in good condition? The alternator isn't designed to constantly recharge a dying battery.
 

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Discussion Starter #6
I understand your need for a stable solution then. Is the battery in good condition? The alternator isn't designed to constantly recharge a dying battery.
Battery is relatively new and in good shape. So aggravating.... otherwise a great vehicle.
 

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2015 4 Runner SR5
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What, specifically, goes bad with the alt? If you get OEM there really should not be an issue, unless A) it was a freak bad unit, or B) something else is causing an issue. Which is why it would be good to know what is wrong with the alts.
 

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Discussion Starter #10
What, specifically, goes bad with the alt? If you get OEM there really should not be an issue, unless A) it was a freak bad unit, or B) something else is causing an issue. Which is why it would be good to know what is wrong with the alts.
Not sure what is the exact issue. The svc techs state "it's gone bad", then replace it under warranty. Oh well, on to the 4th one. Let's hope it lasts!
 

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1998 T100 SR5 2WD
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How good are the grounds and battery cables? Are there any aftermarket mods installed (sound system, lights, high amperage devices)? Exactly what failed on the previous alternators? What tests were performed on the alternators? Has this vehicle been in an accident before? Has the charging system been modified or altered? Have you tested the voltage output of the alternator when it was new/installed? ;)
 

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Discussion Starter #13
How good are the grounds and battery cables? Are there any aftermarket mods installed (sound system, lights, high amperage devices)? Exactly what failed on the previous alternators? What tests were performed on the alternators? Has this vehicle been in an accident before? Has the charging system been modified or altered? Have you tested the voltage output of the alternator when it was new/installed? ;)
Vehicle is box-stock from stem to stern, with no mods or add-ons anywhere. Since all the failed alternators were returned to get core credit, I didn't get a chance to dig into the units and specifically diagnose what failed. When/if #4 kraps out, I'll keep it and tear it down on my bench to ID the weak link. Thanks big time for all the feedback!
 

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2015 4 Runner SR5
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I have heard, not sure this is factual, of reman alternators not touching the diodes in them (meaning they rebuild the other goodies but leave the diodes). That diode can go bad and that is all she wrote.
 
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