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.
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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.
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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.
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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:
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Replaced the alternator and parasitic draw and A/C voltage gone.
O'Reillys is rapidly becoming my "white whale:"
Amen, Ahab.
