Hi All. It's unfortunate my first post is asking for help (hate to be one of those people). Bought an R53 Chili Red Rallye edition about six months ago for my 16 year old son. Have done a lot of work, but have come up against a problem I just can't solve.

Things I've done so far.
- Front Control arm bushings (went through learning to drop subframe)
- Strut mounts
- Struts
- Power steering pump (rebuilt)
- Check SC oil
- Serpentine belt
- PRW Harmonic Balancer
- Intake hose
- Air filter, and couple oil changes now
- Alternator (5 times!)

The problem started with a lot of shrieking noise. We figured the harmonic dampener had come apart, so ordered an aftermarket improved one. But when we got into the job, we figured out it had already been replaced, and the problem was actually the alternator pulley was spinning on the alternator front shaft!! Amazingly it still charged the car fine. The alternator was actually fairly new (done by previous owner); and was a nice looking Bosch unit. Very surprising problem. I've repaired my own cars for years and never seen anything like that.

So bought a AC Delco replacement and installed. Put car back together, and alternator was charging fine at idle. Drove about 15 minutes, and the low battery light came on! Indeed, the alternator had stopped charging.

Removed it, and tried to figure out what happened. Turned out one of the brushes wires had melted right through! So figured it was just a factory assembly issue and put new brushes in. Put everything back together, went for a drive, and same issue after 20min driving or so.

Pulled alternator again. Same thing; brushes wire had melted. So replaced brushes again. This time I cleaned up most grounds/power connections everywhere. Same problem again after 15-20min driving.

Repeated changing brushes again today. Went through all battery wires again; cleaned everything carefully. Measured 14.3V at idle in engine bay and about 14.0V at battery. Seemed like all was fine. Before putting car together, we revved it a lot, cycled power steering, checked codes, etc. Same issue happened yet again.!!!! Just about ready to push this car into the ocean now.

So something I guess is drawing big current, not blowing fuses, but simply melting the alternator copper brushes. Battery charges fine, keeps a charge, and starts car easy. But is there some reason to blame it and replace it in any case? Or maybe my rebuilt EBay Power Steering Pump is causing problems? Electric Fan?

I guess, has anyone else solved a problem like this? I have read of others replacing their alternator multiple times, but never really seen a final solution they found which fixed the problem.

Thanks a lot for any ideas! We're SUPER GOOD and putting car into SERVICE MODE now, haha. But actually wearing out fasteners from doing this so many times.

Nick

 

bummer never head of this before. any new update? i wish i had a solution for you.

are the pulley's stock. only thing i can think of right now is that its being overspun. not even sure that is possible

 

I'm a bit confused with your statement "Measured 14.3V at idle in engine bay and about 14.0V at battery." I understand 14.3V at idle but your battery should only measure around 12.6V without engine running. I'm also not seeing that you tested the alternator that could have a malfunctioning regulator. Another thing to check: your grounds if bad could be overloading the alternator (increasing resistance) and causing it to run hot.

 

Both those measurements were with the engine running. Just indicating there was 0.3V drop on the cable from front of the car to back where the battery is. To be expected I think.

I did clean every ground and power connection.

I believe now I simply have a crap alternator with a short probably in the rotor. I'm going to buy another one and see how things go. Essentially I realize I've been blaming the car as the problem, when it could just be a problematic alternator.

I'll post back here once I've installed and run the new one.

Thanks a lot guys for your ideas.

 

Yes. There are many stories about bad rebuilds. I am kind of in that movie. Ours failed over the weekend. I have a rebuilt Denso coming from FCPEuro. I know that the original is Denso. Will let you know in a few days.

 

Denso rebuilt unit in from FCPEuro. That with a new tensioner, idler, and belt. Running since night of Aug 14 - 150 miles or so. Fingers crossed.

 

All good now?


Edit: Thanks for the update.

 

Good timing to your question. Monday night I removed the alternator yet again.

Tuesday morning we brought it to a local auto electric place (where I should have gone to begin with honestly!) I explained the issue with the brushes wires failing after 15min, and suggested maybe the rotor had a internal short (from what I'd read).

When inspecting/diagnosing, they found all kinds of things wrong including confirming the rotor was failed! We asked them just to fix it all. I didn't want to chance another AC Delco unit (by returning my original purchase).

So last evening (Wednesday), I put the repaired alternator back into the car. We took it for a good long test drive. No issues cropped up!!

So I think it's all good now. We'll see how it does over the next few days though. I'll report back again if anything comes up.

Thanks everyone for your help.