PDA

View Full Version : Whine from alternator????



tabboo
04-12-2011, 06:03 PM
Took the G8 6 litre to the dealer for whining noise when just after it starts & it whines a little when you rev it in park. Dealer said it is coming from alternator & said the wine is normal.
Anyone else have this noise?

SpeedRacerX
04-12-2011, 06:12 PM
I've noticed mine getting worse lately...

bigtreepu
04-12-2011, 09:11 PM
I've had it forever. Normal to me.

MongosG8
04-12-2011, 09:18 PM
yeah ..was told the same thing when I purchased mine 2 years ago.. never had a problem so I consider it normal

SpeedRacerX
04-13-2011, 05:21 AM
I like to think I have a small supercharger under the hood and that's where the whine comes from. LOL.

G8GT721
04-13-2011, 05:33 AM
I like to think I have a small supercharger under the hood and that's where the whine comes from. LOL.

I had a guy at my work ask me that, before the turbos


Sent from my iPhone using Tapatalk

SRG963
04-13-2011, 05:34 AM
Normal as stated.

MoonPie
04-13-2011, 06:29 AM
I've heard mine once or twice, can't remember the last time I've heard it it's been so long

bjhayes
04-13-2011, 08:47 AM
Whines like a any other 2 year old... Even had someone ask me once what type of supercharge it had.
I've seen it on a few cars... My old '99 Suburban whined too like this but my '02 Silverado does not. Go figure.

Napalm
04-13-2011, 09:54 AM
no it is not normal. No alternator should whine. I think my car is doing it too. occasionally.

Typically, alternator whine when running can be attributed to A) bad battery not taking change correctly, or B) corroded terminals, usually on the ground side of things

Typically. I intend to check my car this weekend.

SpeedRacerX
04-13-2011, 10:23 AM
no it is not normal. No alternator should whine. I think my car is doing it too. occasionally.

Typically, alternator whine when running can be attributed to A) bad battery not taking change correctly, or B) corroded terminals, usually on the ground side of things

Typically. I intend to check my car this weekend.

Thank you for the heads up. I'll check mine too.


On a related note: sometimes when I hear Whine, I break out some nice bread and cheese too.

Napalm
04-13-2011, 12:06 PM
I can see where a bearing might make noise but high pitch whining is usually related to the rectifier circuit. Or it has been with every other car I have owned.

Granted the G8 computer is modulating the field effect on the alternator windings during load condition changes. It might be normal, but I've never heard another new age car do this.

Pet peeve of mine. I had whine on my GTO not to long ago and it turned out to be a weak and dieing battery.

bigtreepu
04-13-2011, 07:14 PM
Mine's been there since day 1. Not that that makes it ok, but my original battery from 2.5 years ago is still working, so I don't think it's that, and I they aren't/weren't corroded. My 2c.

Napalm
04-13-2011, 07:18 PM
Are you sure the whine if from the alternator?

Torque converters can whine, and can air boxes.

I sometimes wonder, my car has noise, but really I can't tell what exactly it is coming from.

jnak
04-14-2011, 05:27 AM
I think almost every G8 has this problem. It's definitely an electrical whine, it's identical to the whining noise I would get in my old cars when I installed aftermarket stereos in them.

Napalm
04-14-2011, 05:39 AM
has anyone ever checked the voltage, and AC ripple at the battery terminals?

the way my noise comes and goes, usually on cold start ups. makes me think that its related to BCM alternator field effect control. (I'm sure the manual uses another term).

basically on these cars (and most built after 2005) the alternator strength and output is controlled by the computer (and I assume BCM but it could be ECM) such that the alternator only produces amperage for given load + x % to keep the battery topped off. IE, with engine running, radio on and AC off say the load is 85 AMPS, then the computer commands the alternator field such that it produces 96 AMPS. The computer monitors the battery condition etc, and all should be well. If you cut on the headlights, then demand goes up 18 amps then alternator load will go up say 20 amp.

the numbers are just a example, I have no idea what the real values for the G8 are. I also assume the G8 uses this scheme as most newer cars today do this. it allows for the alternator to pull less drag on the engine and thus save some fuel. In theory it also allows for better battery management and power stabilization. note I said in theory.

This load adjustment is done by modulating the field in the alternator windings, the rectifier circuit has to modulate as well to make up the differences. Amps and voltage go hand in hand so things have to be shifted and balanced in the rectifier as well.

Maybe it is normal. but I have never heard another car make noise like that. I do find that my noise goes away,but I don't like it.

Napalm
04-14-2011, 05:39 AM
Lowered battery capacity and increased battery resistance will make these matters worse. usually.

SRG963
04-14-2011, 05:41 AM
According to several dealerships, the alternator whine on the G8 is normal. Even though they stated it was normal, the manager was going to replace my alternator to see if that cured the issue. I didn't think it would work, most everyone that owns a G8 expierences this. I get it on every cold start for a second or two.

BigRed585Lbs
04-14-2011, 06:51 AM
I've had it in almost every vehicle I've owned, but the subsequent owners of these vehicles report no such problems.

There I go; whining again.

foreosu
04-14-2011, 08:32 AM
Been there since day 1 for me, too. No issues whatsoever, so I consider it normal.

cvidt
04-14-2011, 10:14 AM
normal for a stock g8. But a long time ago I saw a thread where someone added additional grounds to they're battery/engine and the noise went away.
Haven't tried it myself yet though. The only time i notice it is when my radio is on aux input

alex94z
04-18-2011, 08:50 AM
I've had whine since the car was brand new. No one has seemed to find a fix. I also hear it over my factory bluetooth when on a call. SO ANNOYING!

Sephiroth
04-19-2011, 04:00 AM
I like to think I have a small supercharger under the hood and that's where the whine comes from. LOL.

I thought the same LOL, is that what that is? Now that I think about it.. my 100K+ Duango 5.9L made a similar noise.

Napalm
04-19-2011, 06:23 AM
The idea of adding another ground sounds pretty attractive. Especially with the battery being so far away from the alternator. surprised there isn't one at the battery and the rear fuse panel.

Sephiroth
04-19-2011, 07:55 AM
The idea of adding another ground sounds pretty attractive. Especially with the battery being so far away from the alternator. surprised there isn't one at the battery and the rear fuse panel.

but on another car with the battery in the front and short ground wires? I don't think I remember it being as audiable when accelerating, but the idle noise was definitally the same in the Dodge.

JMS
04-19-2011, 09:10 AM
I had the whine too, the dealer said it was a pulley and changed it. Noise went away for about a year. Now its back. Will probably take it back in and see what they say now.

Napalm
04-19-2011, 10:42 AM
but on another car with the battery in the front and short ground wires? I don't think I remember it being as audiable when accelerating, but the idle noise was definitally the same in the Dodge.

Current loss over distance. IE short cable or larger cable needed. (IE, EG, WTF?)

AVIDMOTION
04-19-2011, 09:27 PM
I have had it too for the life of the car. I hate it.I ALSO have a problem with my Power steering unit. My power steering unit also makes a surging sound, like you can hear the fluid squishing through the hose. I flushed the reservoir 3 times to no avail. I have 1005.2 miles left on my bumper to bumper certified GM warranty. My car is at the dealers for every issue I have, too numerous to list here, let you know what they say about the alternator and power steering unit....

Napalm
04-20-2011, 05:42 AM
there is fluid in the alternator? somewhat different, you mean it has oil in it for lube. or is it oil for a giant capacitor?

Or are you just describing a noise?

AVIDMOTION
04-20-2011, 05:51 AM
Crap I meant power steering unit sorry

Napalm
04-20-2011, 06:19 AM
Crap I meant power steering unit sorry

No worries. have the fluid changed. it gets a bit old during shipping and I don't think they actually put Dex IV in them from the factory. Most GTO's had the same problem. Mine went away with a fluid change. well 2 actually. short of droping a hose off, letting it pump dry and so forth. you can't get all of it out. (there is quite a bit in the rack too)

so with suction pump in hand (mityvac from parts store or you can use a turkey baster or battery filler) I emptied the res. then refilled with mobil 1 ATF. drove for a week, rinse and repeat, drove for a week, rinse and repeat.

Steering got smoother, no noise. I will do the same shortly on the G8. as well as replace the brake fluid.

[/thread hijack]

AVIDMOTION
04-20-2011, 08:38 AM
Talked with Pontiac, said they put the alternator through their tests it tests out fine, said could hardly hear my whine, others much louder, battery tested ok too. Alternator listed as normal. No word on power steering pump yet, but I did flush it 4 times already to no avail.

djerickd
12-31-2012, 02:34 PM
Talked with Pontiac, said they put the alternator through their tests it tests out fine, said could hardly hear my whine, others much louder, battery tested ok too. Alternator listed as normal. No word on power steering pump yet, but I did flush it 4 times already to no avail.

this fixedd it for me

http://www.g8board.com/forums/showthread.php?t=45422