Very Soft Alternator Squeak

[Vikas]

I hope you checked the voltage with full load and with RPM about 1000-1200. If that number is not over the resting battery voltage, the alternator is on the last leg.

Given that a typical alternator will need replacement at 100-150K miles, you might as well get it replaced at your convenience rather than when it dies unexpectedly on you.

- Vikas

 

[sciphi]

Vikas, I've checked the PCM-reported voltage with the ScanGauge while the car is driving at interstate speeds running about 1500 RPM. That's always 14.2-14.6 volts. This jibes with the idle readings I got with my multimeter.

 

[4ever4d]

Agree.Bearing is most likely cause.

 

[antonmnster]

On my 250,000 mile BMW, I just popped the alt out, carefully pried the seals off the bearings, and loaded them up with grease. Put the seals back on, put the alt back together and I was good to go!

New bearings are ideal, but an hour of putzing and $.03 worth of grease is a lot easier.

 

[rpn453]

I've had that happen. I left it alone until it got really loud on startup one day and then replaced it. My buddy and I have had bad luck with our local alternator rebuild shop, so I went with a brand new lifetime-warranty Hitachi.

 

[Nick R]

I would get it taken care of as soon as is feasible. Don't want to end up with the belt flying off at highway speeds. Loss of cooling, power steering.... Wouldn't be pretty.

Question about alternator bearings though- do they use Bushing type bearings, or do they use actual ball/roller bearings? Or does it depend on the automaker, and model?

 

[mechtech2]

One more thing, if a diode is bad, you can sometimes hear a high pitched squeal.

Auto parts tore rebuilds are iffy. The guarantee is good, but you probably will have to use it.
Dealer rebuilds or Bosch are very good.

 

[rslifkin]

^ Agreed on the noise. When I had a diode going (for about a year and 11,500 miles from when I bought the Jeep to when it actually blew), I had a whine from the alt that got louder with more load. I had no idea what it was from until it shorted.

 

[rpn453]

Originally Posted By: Nick R
Question about alternator bearings though- do they use Bushing type bearings, or do they use actual ball/roller bearings? Or does it depend on the automaker, and model?


I've only seen cartridge ball bearings.

 

[sciphi]

I called the local rebuild place, and they sounded not too thrilled about working on it, saying they'd need to see it off of the car. Given that I need the car, I'll likely get a remanned one. There are NAPA and Advance stores within 2 miles. The NAPA alternator and the Worldwide from Advance are both available with a lifetime warranty. Right now I'm leaning toward Advance given the discount coupons and better warranty coverage.

 

[Vikas]

My mechanic likes Bosch remanned although I would personally prefer Denso for Japanese vehicles.

 

[sciphi]

Bringing this to half-closed...

Installed a Worldwide remanned alternator yesterday. I had the counter guy put it on the tester before installing to listen for any funny noises and to see if it worked. It passed that informal test, so on it went. It works fine, no squeaks/squeals, and my voltage is right where it should be.

I'll re-open the thread if any difficulties arise with this remanned alternator.

 

[sciphi]

Or not...

The remanned alternator is on its way out after a day trip of about 250 miles. It's making a nice squeal. Looks like a lifetime of replacing this part. Drat.

 

[Herz]

I have had good luck with NAPA new alternators, for like 20 bucks more that also carry a lifetime warranty, I would have gotten one of those.

 

[sciphi]

I just may if a good one isn't in stock.

 

[sciphi]

Or, another twist...

That squeal went away once the alternator got a chance to sit, and hasn't come back after a 40-mile trip. It's barely making any noise at all now, voltage is fine, and the rectifier is just barely warm.

Figured I'd keep updating the saga for any folks searching about remanned (remanufactured) alternators in the future.