Gen 5 Camry 2.4L Low Alternator Output

[BKSmooth]

In short, 2005 Camry 2.4L, 135,000 miles, alternator terminal = 13.35V @ idle (low beams on, nothing else). At 2,000 RPM improves only to 13.6V (!!!). With AC on high and hi + low beams on, it drops to 12.7V. The twist: battery + alternator test "good" per O'Reily's, Autozone, and my DieHard batt charger.

Details....

9 months ago (123,000 miles), my batt was weak (~11V) after sitting 3 weeks. I fixed a *slight* parasitic drain (~180 mA) and recharged the battery. Alternator was weak (13.2V idle, 13.4V @ high RPM) but tested "good" @ A-Zone & O'Reily. I said "uh, I don't think so" and replaced the alternator anyway with a remanufactured one from O'Reilys. Immediate improvement: 13.9V idle, 14.2V @ high RPM. Was still the same 5 months later when I checked again.


Some Considerations I Had:

Belt: it IS the factory serpentine belt (yeah yeah, I know) but seriously... no cracks, no nicks, and it is taut as hell -- I'm no weenie and I struggled to get the belt back onto the pulley when I replaced the alternator 9 months ago. Having replaced many serpentine belts before, this one definitely seems fine.

Belt tensioner/worn bearings in one of the pulleys/etc.: I guess it could be? But there's no strange noise under the hood and it idles fine and with no power steering issues at low speed etc.

Battery: also tests good on 3 different testers... holds 12.5+ OCV @ rest. I discovered it was 12.1V on a random test last week, recharged it manually, and started monitoring it -- gradually weakened to 12.3V over a week presumably due to weak alternator output not recharging it. As a control, I swapped in the batt from my wiife's Scion Xa with no change in alternator behavior.

Parasitic drain causing voltage drop: Checked that, it's <50mA @ rest.

You might say (like O'Reilys) "what's the big deal, 13.3V is in range." Well... maybe technically. However, when brand new in 2005 and again in 2008 after replacing the factory battery it was: 14.1V idle w/ low beam, 14.4V @ high RPM in neutral, only dropping to 13.7V @ idle with hi + low beam, AC and fan on high, and all 4 window motors engaged.

O'Reilys declined to replace the alternator insisting it's "just fine and anything more than 13.6V could blow up the battery" (I was unable to contain laughter on that one), but I didn't push hard about it.

Any and all suggestions and assistance is appreciated!

[BKSmooth]

Thanks for all the replies everyone!

Here's a follow-up for anyone running across this:

Despite my reluctance to do so, I replaced the serpentine belt. Output is still on the weaker side (13.7 idle, 14.1 at 2.2K RPM) but better. I guess the belt must have stretched out a few millimeters or enough to take a little tension out of it.

[islandboy57]

Interesting, thanks for the follow up!

Lately I've been noticing my lights dimming when my AC compressor kicks in. And I don't mean it's dimming for a second then going back to normal.. It stays slightly dimmer until the compressor kicks off again. My car has never done that before but I know it's not unusual for the lights to dim for a second while the compressor kicks in (after all, it's a high load) - I drove my aunt's '09 Civic last night, turned the AC on, and saw the lights dim for half a second before going back to normal. Like I said, mine stay slightly dimmer until the compressor kicks off again.

I was thinking it was just the alternator but now you're making me second guess myself. Like yours, my serpentine belt looks to be in perfect shape with no cracks, I have zero odd noises/squeals, and the car drives great. Sounds like it's a combination of a slightly worn belt and a merely adequate alternator from the factory.

I'll probably just live with it for the time being. It's just annoying to see my lights dim and my idle drop enough to make it vibrate for a second or two. Probably doesn't help that I installed OEM foglights, which is just more work for the alternator..

[gdanaher]

Your problem might be tghe volt meter itself instead of the alternator. Use a different volt meter. 13.8 volts plus or minus is good. Anything below 12.8 would be a concern.

[BKSmooth]

Originally Posted by gdanaher

Your problem might be tghe volt meter itself instead of the alternator. Use a different volt meter. 13.8 volts plus or minus is good. Anything below 12.8 would be a concern.

Thanks for the suggestion.... but.....

Originally Posted by BKSmooth

[B]also tests good on 3 different testers...

I've got a couple multimeters of reputable quality and both did read within .01V of one another when used half a second apart. But that is a great suggestion.

[BKSmooth]

Originally Posted by islandboy57

I'll probably just live with it for the time being. It's just annoying to see my lights dim and my idle drop enough to make it vibrate for a second or two. Probably doesn't help that I installed OEM foglights, which is just more work for the alternator..

Personally, I wouldn't see it as a critical task either. In my case, the low output seemingly resulted in the battery not getting charged due to my relatively short commutes lately (<2-3 miles/5-10 mins).

I didn't mention it in the OP, however I did also have the tach drop to ~550-600 RPM (and output voltage to 12.7V) whenever I'd have the AC compressor on, blower motor on max, hi + low beams on. It'd even drop to 12.6 if I engaged all 4 window motors. It was truly pathetic.... way the hell out of spec. But now it's hanging out @ 13.6V at idle when those things are done and the fast idle picks up to compensate in a timely manner (1-2 seconds vs. basically not at all before).