Electric sounding whining noise?

[oldslss]

hey everyone I took delivery of my "new" lss last saturday so far this entire week has been just cleaning the *dang* thing. so much grime from the old guy who owned it.
anyways as soon as left with the car i noticed it was was making a whining noise, almost electric sounding that follows engine rpm, not speed.
I had seen/driven the car about a month prior to purchasing and it did not make the noise. the only thing that changed during that month with the car was that it had a brand new alternator, which seems like a unlikely culprit but I can't think of anything else that would change pitch while the engine accelerates and decelerates, and make an electric sounding whining noise. its also louder inside the car with the windows up then outside hood open staring at the motor idling. I can tell you its absolutely not power steering whine, my Riviera makes that noise all day everyday. I even tried to follow the sound to find the source but its proving a difficult task. Anybody experience something like this before ?

[MKMike]

"Brand new alternator" might be the key.
Many people have their mechanic put in a "new" alternator, which is actually rebuilt.
The quality level depends upon who does the rebuilding.
Even if new, there can be defects.

You may have success pinpointing the source by listening through a piece of tubing, such as pvc pipe or tubes from household or shop vacuums.
Some people even use a very long screwdriver to transmit the noise--listening through the handle.

If that doesn't help you, then take the belt off and start the engine but don't run it for long w/o the belt, just long enough to be sure the noise vanishes.
If the whine disappears, you'll know it's a bearing noise--likely from the "new" alternator.
After you shut it off, you can spin pulleys by hand to determine if any is the source.
Put your hand on the body of whatever has a pulley and feel for vibrations while the pulley spins.
A bearing should spin smoothly and there shouldn't be any wobble or excessive play.
If you can feel roughness, the bearing is bad.

If the noise stayed, you can hunt for other suspects.

Since the noise is louder inside the car, listen at the speakers and make sure it isn't a noise coming from there.
Check the transmission fluid level and be sure that isn't the source of the noise.

Let us know what you find.

[Sirius]

If the old alternator was hosed (making that assumption since most people don't change an alternator just because they have $120 laying around), what condition is the battery in? If it's low or won't hold a charge, it could be that the new alternator is constantly charging. I've heard alternators whine a bit when put under load. Get under the hood and try some of the things mentioned above.

[oldslss]

I actually did the screwdriver technique prior to posting this! didn't help with the weird electrical noise but now i know why i had a weird howl at idle. one of the pulleys is on its way out (accessory belt underneath the alt) already ordered a whole whack of stuff for the car including all the idlers just waiting on parts arrival. the battery is a pretty fresh delco only 2 years old says the date on it.

but good idea on taking off the drive belt, completely slipped my mind to try that :p tomorrow il give that a try after work gotta bring some tools home with me, if the noise goes away il swap the riv alt onto it.

[oldslss]

Alright everyone i'm back with no good news really.
Took of all the belts noise was still there, it still followed engine rpm's. Me and a buddy tried to look all over for something but were stumped. The only thing i can think of that still rotates and goes with engine rpm with no belts is the trans. but i have yet to hear any 4t65 make this noise. the noise is also definitely coming from the front of the car like doors forward. it seems to be louder underneath the car as well. that's all we can figure out.
i'm doing the lim gaskets, headers , exhaust, 3.4 pulley, oversized rad (From my riv)!!, and a whole bunch of other stuff to the car so its currently pretty torn-down, trying to get it ready for the meet on the 25th! hopefully when its back together i can get the noise pinpointed and fixed.

[96 SSEi]

cam will spin with rpm, wont it?

[oldslss]

Alright guys the cars back together running great. After some more snooping around it seems like its the trans whining, definitely whines louder in park or neutral, but still whines in drive and goes up with engine rpm. its just quieter when stopped in drive because of the low rpm. I am going to be dropping the pan for a fluid/filter change when the transgo shows up. so i'll report back after that and see if there is any change. anyone know what could be causing this noise inside the trans, pump maybe??

[SSEBonne4evr]

You will find out when you drop the pan if there is debris in it and a clogged filter.

Did you check out the power steering pump first?
I had this whining problem and a pump fluid change did the trick.

[oldslss]

I ran the car with no belts, noise was still as loud as ever definitely not any of the accessories