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O'Reilly Ultima Alternators

03-06-2006, 01:19 PM
I am about to replace my remanufactured Ultima/O'Reilly Auto brand 140 amp alternator in my 1998 Aurora for the third time. The first one I bought as a replacement for the factory original never charged properly out of the box. This second one has lasted almost a year. Now, I am going to put a third one in tonight/tomorrow. Has anyone else had problems with these remanufactured alternators? They have a limited lifetime warranty, but it is still a big pain to have to keep changing them out like this.

03-06-2006, 06:09 PM
some rebuilts(and new) arent worth the time to put in.
I bought a lifetime warranty on a 95 Firebird one from Pep boys
and its been replaced 8 times in the last 6 years.
They were so bad with rebuilts that Pep boys sold only new ones in that style.
Too many amps in too small a case,plus too hard to get rid of heat.Caddy tried a liquid cooled one to help but cooling leaks were worse than alternator problems.
I have a local shop that does a great job (replaces everything except case) for $100.
Only a 1 yr warranty but that doesnt mean they last only that long.
Feel good that you dont have a 95, not many of those around.
New GMs are about $200.

03-07-2006, 09:08 AM
I replaced the alternator last night. It was tested and was definitely bad. I live in a small town and 140 amp alternators are fairly rare to start with, so they really couldn't tell me if these alternators have a history of troubles. If I keep this car much longer, I will be their history of troubles. If I wasn't so strapped for cash when I had purchased the original Ultima a year and a half or so ago, I would've spent the extra money and got a new one from the factory. I may have to come up with a quick release velcro strap for it to making changing it out easier. :lol:

03-07-2006, 08:05 PM
just went thru it on my 95 rora.
got a used one(tested it first) for $20.
Not so hard to replace once you get used to it huh?
I can change the one out on a 95 Firebird in 10 minutes tho.
Wish I could say the same about the rora.

03-08-2006, 10:17 PM
What voltage range should a new alternator be charging? I just put a new A.C. battery in (880v) and it is charging just like the old one at 15.5 volts. Isn't that a bit high? I was thinking about 14 max... I have a 95 Aurora..

03-09-2006, 06:53 PM
I wouldnt be alarmed if its only .5 volt too high.
Check it at battery with a good VOM and see whats up.
My 96 was 15volts when they replaced alt under xtend
warranty and its been OK for 4yrs now.
Ive still got the same Optima battery for last 6 yrs so it must be OK.
Ive had alot of problems with Delco batteries had 3 break at positive
terminal and leak acid,and wont buy any more of them.
For the Aurora it just doesnt make sense to use a battery that will leak
and possibly need mantainece.Thats why I use optimas.

04-06-2010, 05:11 PM
I was thinking about replacing my bad alternator in my 03 escape with the ultima brand, but I think I will go to the dealer. The original lasted 95,000 miles so I think I can expect the same from the oem new replacement. Warranties are good, but only if you need them only once. I wouldn't want to warranty one part 8 times in 6 years. I have better reasons to spend time on my back - like relaxing on a Saturday evening looking at the stars with a Martini in-hand.:grinyes:

04-09-2010, 10:51 AM
15.5 is normal. Anything under 16 or so is fine.

Generally when the alternators are rebuilt, the bearings are replaced but they reuse the regulators. So when you put your reman in, its just a matter of time before the regulator fails. If they do replace the regulator they are generally of low quality. I would recommend replacing with a reman ACDelco unit that has had the electronics replaced with OEM parts. This is what a dealership would use.

Declo/GM Part number is 88864258 for 95-99. $35 core. $150 at

$130 on, but they will hit you up for more shipping. This alternator should last another 10+ years.

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