Outside my car you can hear the alternator whining pretty loud. I have heard this on other cars but mine seems a bit louder maybe. I checked the battery with the engine rpms up and see that it is producing almost 15 volts. Could something still be wrong with my alternator? Diode? How can I test for it. I had my original replaced with a rebuilt a few months ago. The first one had a bad bearing that made noise. They replaced it with this one and it doesn't make the same noise as the other one. The last one made a sqeaking noise not a whining noise that varies with rpms.
Since the last alternator change I installed a system. The whole time I have had an alternator whine problem through my amp/speakers. It seems to be worse sometimes than others. I have tried to fix it every way I could think of. Now I am hearing it outside the car and wonder if the alternator is to blame for the excess ripple.
I had an appointment for a local audio shop to look at my system tomorrow and diagnose the whine so if you guys think that it has to do with the car and not the system please let me know so I can cancel and get the car looked at.

 

voltage regulator is bad i think, i thsould be at 14 volts, its overcharging and itll kill your battery. you need to replace teh alternator.

 

My multimeter is not digital so it may have been a little less than 15 volts, im not sure. It measures 13 volts with the car off and 14-15 with the car running.

 

invest in digital, i bought a digital for that same purpose because teh analog was giving me an estimate.

 

Yeah 15 volts is a little excessive. Take it to autozone. The machine can diagnose a bad diode problem, however with a whine and the symptoms you say, I doubt its a diode problem. Sounds like a deal with the voltage regulator and its internal so its a new alternator. If you replaced the alternator recently go back and see if your warranty is still valid.

 

Thanks for the answers. I will take it to autozone and get it checked out tomorrow before I go to the audio shop. It states right on Autozone's website that they can test for a bad voltage regulator so I will update this tomorrow and tell you how it went. Maybe I should ask santa for a digital multimeter huh?

 

$17 bucks at walmart, it goes a long way though. you can use it to test alot of sensors and things of that nature. household use as well

 

on harborfreight.com, I found a cen-tech digital one for $4 awhile back (tho I did order other stuff along with this at the time). The same one sold in wal-mart for $20.

It's good to have an analog one too tho, for reading codes on older cars for instance. I dunno, but I find them easier to read sometimes (analog)...but maybe I'm used to 'em since I've played with 'em since I was 10-12.

 

Well I had the alternator tested. It was working fine and the machine indicated that there weren't any bad parts in it. It still seems noisy to me though...even without it being amplfied into my amplifier/speakers
The stereo shop tried to "ground" the shield of my rca's to the back of my h/u...didn't work. I discovered later that to accomplish this, they cut off one terminal on each rca cord and wired some other cheap connector spliced with a ground wire to each. They ruined my rca's. Since they couln't fix it they didn't charge me for the "work" though. At least I had some old rca's laying around. I have tried everything I can think of to fix that whine except a filter on the power lead on the h/u and regrounding the h/u. Im not sure where to reground it though without making the wire real long. I have been told that it rarely works either. Has it worked for any of you?

 

I just had my alternator replaced on my 99 SE. I noticed tonight that when I turn my headlights on, I hear a whining noise coming from the alternator area. When I turn the headlights off it goes away. Is this maybe a fualty altlernator?

 

I had a similar problem. it turn out to be the bearings in the alternator was on its way out, took it to a alternator reco guy and he fixed it all up for me.

 

Yes, sounds like the alternator is working fine, but the bearings are probably on their way out. I was having an alternator issue as well and the bearings were whining pretty loud. Eventually the alternator died and I just replaced it and the whining noise was gone.