Can alternators make noise?

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I know, sounds like a silly question, but I've never had an alternator problem unless it was dead. It didn't make any noise before expiring.

Earlier this year, the 2011 Regal CXL with the 2.4L engine developed what sounded like a belt noise. I promptly had the belt replaced (at 85K miles or so). However, the sound (a metallic whine, though not loud) continues. When the car is cold, I don't usually hear it on start-up. I do hear it after 20-30 minutes of driving, say to work or back home, and then when I re-start the car it crops up again. It seems to come and go, does *not* happen only when the compressor is on for A/C, and sounds mechanical and not like a squealing belt. The sound seems to be coming from the alternator or someplace close by. It's not the power steering; the fluid is fresh, changed earlier this year by yours truly, and at the proper level, nor does the sound vary when I work the wheel back and forth.

Alternator?
 
GM was famous for alternator whines back in the day of the 65 amp. But their newer ones seem to be quite quiet most of the time. Sometimes they have bad bearings and this can sound like a bad wheel bearing at times depending on how bad it is.

Does your alternator have a clutch (de-coupler pulley) on it? If so this could be indication that the clutch is starting to go bad.

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Had this happen last year on my lexus. Alternator sounded like the power steering pump was going bad. After 6 months of very intermittent noise, finally threw the battery light.
 
It could be the alternator, this is a standard 6 groove GM unit, no clutching. It could be a few things eg idler, tensioner pulley, etc.
A mechanics stethoscope should help locate the culprit if you don't have one pop the belt (mark the outside so you can it back on in the same direction) and spin the individual pulleys by hand feeling for any roughness and play.
 
They can make all kinds of noise.
About a year ago, my Ford work truck developed a "thumping" in the alternator. It honestly sounded like a wood pecker on steroids. When you put your hand on it, it felt like something was going to come out the side of it. I wanted to tear it apart to see the problem, but it was just exchanged out.
 
Originally Posted by NYSteve
Had this happen last year on my lexus. Alternator sounded like the power steering pump was going bad. After 6 months of very intermittent noise, finally threw the battery light.

Yes, that's about what it sounds like. No CELs yet. The car is otherwise quiet at idle and at speed, and while it burns some oil, it still gets about 21 mpg overall with 70% city driving.

Shop time next week, I guess. Thanks. I'll let everyone know what the problem was.
 
Yep, they can make noise. My Saturn started making a faint whine that got louder if I turned the lights on. Changed in pitch with engine RPM. Wasn't a slipping belt. The laminated plates in the stator can become loose if the varnish that holds them together cracks. Worked for while, but replaced it to head off any problems. Noise was gone after that.
 
I had a loud whine from ps pump or alt for two days. Yesterday my car went into electrical failure , dead battery and won't rev/drive without battery pack
 
Well let's see.You have a rotating machine being driven at twice engine speed with a rotating field inducing A/C current in stationary conductors and diodes producing an almost straight line D/C voltage. Not to mention being driven by a composition belt and cooled by at least one internal fan. What do you think?
 
Modern alternators still make enough noise that when I retrofit them to old muscle cars with loud engines, I can absolutely tell if they are operating or not.It's not a terribly sharp or noticeable noise, but once you can discern the noise you can never un-hear it.
 
Yes, I had an alternator in an older Regal with the 3.8L engine that began whining. It would get louder as I accelerated, and then back off once at cruising speed. +1 on the idler/tensioner pulley also.
 
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Yah the Rat's alternator is a lot quieter since I replaced the 5 cell battery with a good un. I could also tell when the Bosch 90 ampers needed a regulator/ brush kit. I went to a re-builders and bought a knock-off for $9.18 including tax. It worked well for a 100k miles.
 
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