Alternator Whine ; not related to Ground Loop

**Trench** · 04-29-2008, 11:34 PM

I do indeed have a Ground Loop, returning Ground Loop that is, but I have not had too much time to try and narrow it down.

I am asking a different question though, that was brought to me compliments of my Ground Loop.

As you most know, The general result of a Ground loop is a high pitch whine that changes with the RPM's. Having dealing with my Ground Loop, I noticed that almost the same exact noise I hear, is also coming from under my hood. It's almost like my Stereo is simply amplifying an already existing sound. Is it possible that my Alternator itself is making this noise in addition to my GL?

If this is possibly a known issue/oddity would it be a simply fact that my Alternator does it tough luck, or could it possibly having something wrong with it? IE, perhaps changing it out would remove the underhood whine...

Thank you all,
Dustin

**ArcaneDreams** · 04-30-2008, 01:14 AM

That is standard.

As your RPMs go up...then the noise you hear under the hood will get louder as well.

Just make sure your ground leads are less than 6" long and are connected directly to your frame.
Make sure to scratch the area of the frame you are connecting to as well to get a nice shiny rough area.

If that doesn't work, get an isolator.

**blckwdw** · 04-30-2008, 12:36 PM

same prob, my pc is in trunk though, would I be better to avaid the loops and run ground cable back to battery? it about 3-4 feet.

**ArcaneDreams** · 04-30-2008, 12:38 PM

Never run a cable all the way to the battery. Make your ground wire as short as possible.

**AWehmeyer** · 05-01-2008, 02:47 PM

Never ground to the car's frame--if it's a car that has a frame. IN all cases, the sheetmetal is the best place, and this is where the alternator is grounded. THe body (in a car that has a frame) is isolated by rubber bushings and the engine is also isolated by its mounts. There is usually a connection between the alternator and the engine block (often the bracket). There is also usually a connection between the battery negative or the alternator and the sheet metal of the car. Those connections complete the circuit. Ground to a bare metal point on the sheet metal chassis of the car. Scrape away the paint and use a locking star-type washer. Don't use an existing seat bolt or other similar poiints. Those are often just spot-welded to the chassis.

**ArcaneDreams** · 05-01-2008, 08:13 PM

Originally Posted by AWehmeyer

Never ground to the car's frame--if it's a car that has a frame. IN all cases, the sheetmetal is the best place, and this is where the alternator is grounded. THe body (in a car that has a frame) is isolated by rubber bushings and the engine is also isolated by its mounts. There is usually a connection between the alternator and the engine block (often the bracket). There is also usually a connection between the battery negative or the alternator and the sheet metal of the car. Those connections complete the circuit. Ground to a bare metal point on the sheet metal chassis of the car. Scrape away the paint and use a locking star-type washer. Don't use an existing seat bolt or other similar poiints. Those are often just spot-welded to the chassis.

By Frame I meant body.