LoL, ask me how much O'Reilly brand alternators suck. Go ahead - AMA!

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Sep 20, 2014
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I just have to finally break down and post some deets about how much O'Reilly "ultima" brand alternators suck. I have bashed them for years but I want to go into details as to why. I just checked out my fourth one on warranty since 2015. I just have to giggle at this point. Fortunately, swapping the alternator in/out of this car is no big deal so instead of buying another brand or installing an expensive, non-junk voltage regulator, I let O'Reillys eat the $100 net cost to them every two years. The vehicle is a highly maintained 2002 Lexus ES300 I've owned and maintained a long time, though it has always been another family member's daily driver. Currently it is my older father's daily driver.

NOTE: there is a lesson here, not just me bloviating - test your alternator BEFORE doing an exhaustive fuse check to find a parasitic draw. More below.

Here's how long you can expect O'Reilly alternators to last. Note that I keep very detailed excel spreadsheets of any time I do maintenance on a car, so the details are accurate:

Here's the history of the alternator in the vehicle:
10/2001 - Original alternator installed, 0.0 miles, Kyushu plant in Miyata, Japan.
6/20/2015 - Total Mileage 239,900 - original alternator failed (bearings). O'Reilly "Optima" alternator installed. 239,900 miles/162 months life
2/1/2017 - Mileage 267,200 - voltage regulator failed, replaced under warranty - 27,300 miles/18 months life
9/29/2020 -Mileage 322,420 - voltage regulator failed, replaced under warranty - 55,200 miles/42 months life
9/2/2022 - Mileage 329,775 - voltage regulator failed, replaced under warranty - 7,350 miles/24 months life

Before you ask -the car has never had the stereo replaced, has no parasitic draw, and is well maintained and the electrical system thoroughly tested.

This time the local O'Reillys manager said they were tired of trying to pretend their alternator could work in this car and would refund my money in full and let me get a better brand next time. Looking forward to 2024!

As a note, voltage regulators fail for three reasons - 1) heat, 2) bad ground, 3) under-spec'd and too much draw. The car has no mods, no excessive draw (I've tested, and the grounds are good (inspected). The cheap Chinese voltage regulators in the Mexican rebuilds just can't take even moderate heat and normal draw - not a confusing diagnosis.

This is the car, recent pics, well maintained. Over the years I've done all required maintenance to keep it in top shape - rebuilt the suspension, restored/refinished the interior, etc. Great road car - decent power but the virutes are it is uber easy to drive, smooth, quiet, and visually very pleasing in the cockpit (not a great looker on the exterior - no pride there). Have a monster fun 2010 GS300 AWD also in the "fam" and while a ton more fun, not nearly as well built as "peak Lexus" like this car. It's a keeper as already demonstrated. But back on track - I can't think of a reason it would suddenly start eating alternators once switching from OE to O'Reillys brand other than the obvious.

IMG-4433.jpg


I detailed the interior in 2021 and refinished the front seats and center armrest, but the steering wheels and the rest is still original at 330k miles. Peak Lexus, as they say. 1998-2003 is the generally accepted range.
IMG-4434.jpg


This failure was particularly annoying, the diode failure still left it providing plenty of charging (actually too much now that I realize it) voltage. There was a massive parasitic draw and I tore out every fuse and relay looking for it - engine bay box as well as interior. No joy.

IMG-4112.jpg


After that, I did what I should have done beforehand, which was look for A/C voltage across the battery terminals, indicating a failed voltage rectifier. D'oh:
IMG-4127.JPG


Replaced the alternator and parasitic draw and A/C voltage gone.

O'Reillys is rapidly becoming my "white whale:"

To the last I grapple with thee; from hell’s heart I stab at thee; for hate’s sake I spit my last breath at thee.

Amen, Ahab.
 
Last edited:
Joined
Jan 2, 2004
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California
All reman alts come from a BBB/Remy plant in Mexico or WAI in China. Unless you buy a Denso or Bosch reman, when you open a box store alt, expect to find Chinese bearings and diode/voltage regulator, a sleeved slip end and sloppily soldered brush holder.

I never had to buy an alternator in the last 14 years. I’ll never buy a box store one.
 

Oro_O

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All reman alts come from a BBB/Remy plant in Mexico or WAI in China. Unless you buy a Denso or Bosch reman, when you open a box store alt, expect to find Chinese bearings and diode/voltage regulator, a sleeved slip end and sloppily soldered brush holder.

I never had to buy an alternator in the last 14 years. I’ll never buy a box store one.

This is from the Mexico plant. From the non-labeled but distinctive rear cover stamping I am pretty sure it is Remy. I DID NOT want to buy it at the time in 2015 but my ex put her foot down and said "I want the car running tomorrow!" I gave in, and have regretted it ever since. Hopefully stronger men can learn from my failure, I pass this on largely as wisdom to help our brethren. :)

Every other alternator I've dealt with since then (and before) I've rebuilt myself and are doing fine.
 
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Jan 13, 2016
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Northeast Nebraska
I've had good luck with one from Auto Zone. Mine was making a little noise on start up but after a few seconds would always stop so I let it slide. Then one Sunday morning I was pulling my my truck up to the garage to air up my tires for a 5 hour round trip we had planned that day when it didn't stop so I had no choice. I wasn't going to get stuck paying some garage along the way hundreds of dollars for an alternator. That was five or six years ago, fingers crossed.
 
Joined
Jan 29, 2012
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Canada
The thing about rebuilds, whether box store or local specialist...it's going to be a crapshoot. On some of the older vehicles I don't know if they can even get OE parts anymore like the regulator. Even if they could, getting completely good quality parts cost a lot more and it's likely not worth it for them to be stocking top grade parts for the one off OCD walk in customer. Most of the local rebuilder's business is with local repair shops where cost is more important than that sort of quality. The parts only have to last during the warranty period.

I was considering rebuilding my Ford alternator which should've been straightforward because it uses a seemingly very common voltage regulator. But I couldn't find anywhere that sells that OE Motorcraft regulator, so I just gave in and let a local shop rebuild it and they put in a generic regulator.
 
Joined
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I’ve been very very lucky with my OE alternators...1999 Honda Accord original alternator lasted the life of the vehicles till I sold it with 289,000 miles on it.
Lexus LS460 179,000 miles, still had original alternator when I sold it. Daughters CRV 164,000 miles, still going.

I feel your pain though, aftermarket parts are hit or miss. I currently am having MAJOR ISSUES with Carquest pads and rotors. After the second warranty of pads and rotors within a year, they are now saying that there is a defect in their pads, not their rotors. The pads are causing the rotors to warp because of copper, or lack of copper...or whatever they claim it is, supposedly the metal breaks off, goes into the rotor and causes parallelism. They are going to warranty them yet again, which is nice, except that it’s a pain to have to do your brakes over for the third time in a year.

And Beck Arnley is another brand I’ve had bad luck with in the last few years. You just don’t know what these companies are doing, it’s cyclical. They can’t be trusted. Some are great (for a while), and then those same companies are horrible (for a while). It’s like buying TV’s or appliances now...a change in business philosophies ruins the brand for a few years, they make more money, lose customers, and then switch philosophies again.
 
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Still have my lifetime ALT from OReillys right after they took over from Kragens. ;)
 
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The only time I went cheap on one is on a 2005 ranger. super easy to change and figured it was getting traded in within 3 years.
Worked out ok
the reman motorcraft was 3.5x more expensive with a 12month 12000 warranty.
or 6.5x as expensive installed by dealer.
or 8x as expensive for a new one installed at dealer.
 
Joined
Oct 7, 2012
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Staten Island, NY
XV30 platform 🥰

One day I'll find a nice 05/06 with the AVS and Heated+Cooled seats, to perhaps replace my Camry

Which is pretty much the same car (ES330/SE V6) both were Japan produced, lesser models were TMMK manufactured

I wound up putting a Denso reman in mine, but I ordered an upgraded 150amp unit for a Sienna/Highlander

Because I prefer having extra capacity over the stock 100

The TYC lasted about an hour before it wouldn't charge

Aftermarket parts be garbage these days 🙄
 
Joined
Oct 7, 2012
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Staten Island, NY
The only time I went cheap on one is on a 2005 ranger. super easy to change and figured it was getting traded in within 3 years.
Worked out ok
the reman motorcraft was 3.5x more expensive with a 12month 12000 warranty.
or 6.5x as expensive installed by dealer.
or 8x as expensive for a new one installed at dealer.
I had a Motorcraft reman that was bad out of the box, even before installation

Not a fan of them anymore IMO
 

Oro_O

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XV30 platform 🥰

One day I'll find a nice 05/06 with the AVS and Heated+Cooled seats, to perhaps replace my Camry

Which is pretty much the same car (ES330/SE V6) both were Japan produced, lesser models were TMMK manufactured

,,,

Yep - not a classic "looker" but a great car. I agree the JD manufacturing makes a difference. I've driven quite a few samples from 02 to 06 and they all feel the same. Small advantage to earlier ones as they still have a transmission dipstick making maintenance a lot easier (I'm a bit of a stickler about transmission maintenance), but that's not a deal breaker.

One thing I'd like to try is an LS430 of that vintage (01 to 06). I know guys on ClubLexus who've had all the LS models since new, and still say they have not built an LS as well as that generation, it was the pinnacle.
 
Joined
Oct 16, 2010
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california
I bought an autolite reman alternator from Kragen, 2005 era.
Lifetime warranty employed at least half a dozen times till 2019 when oreilleys claimed to have no record of me ever buying an alternator.

Externally regulated.

I later found the sliprings installed to wrong depth on shaft, and one brush bridging both sliprings.

Honed the out of round warbly slip rings, modified the brush holder to align, tries to incrrase thermal.teansfer.from rectifiers to casing, and reduce resistance where I could, and returned it to service 2 years ago without further issue.
 
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