I had another thread but this is another noise entirely. Read here for background.

https://www.cobaltss.net/forums/2-0l...sioner-267147/

I thought the noise was still there...but it seems its another noise entirely.

1. I JUST replaced the s/c coupler like 4 hours ago. Refilled with fluid to spec and reinstalled.

2. Noise sounds like the timing chain tensioner but more subdued....sounds like a whirring..metal on metal noise...like a screwdrivers is caught in a cooling fan. Lol. I am trying to find a vid that sounds similar.

3. THE NOISE IS NOT PRESENT WHEN THE BELT IS REMOVED AND THE ENGINE IS STARTED AND RUNS.

That leads me to think its either.....the idler pulley....tensioner (which has a oversized pulley with say.....10K on it)...or the a/c compressor (clutch assy). I have worked at a dealer many years and have heard it all lol.

Im stumped. I can ask for help, lol. Any thoughts or input? Car runs fine...no loss of power or boost. I inspected the s/c and couldnt find anything foul. Rotors looked good....doesnt sound like a bearing.

PLEASE help

 

So you have determined the sound is coming from one of your belt driven accessories....
"Whirring" noise makes me thing you have a bad bearing on one of the accessories. Spinning each one by hand should indicate which one is causing the problem. I have had a bad A/C unit cause this type of noise, but it could be any of them really.

I know you replaced the coupler, but this sounds more like a bearing noise....are you sure it isn't the supercharger?

 

I say whirring but..............its like a metallic grinding/whirring noise. I spun the s/c and didnt hear anything and it doesnt sound like a bearing. Hmmmm.

 

Look at the tensioner ARM... It causes tun of issues and look st belt for wear.

 

pardon? tensioner arm? not sure what you mean. its tightened down and has some lateral play but as far as i know its always been like that.

 

From the video you posted in the other thread it almost sounds like it could be the timing chain. We had a Grand am at work a few days ago with a timing chain issue and it sounded similar to sound in that clip posted in the other thread.

 

Yes and thats fixed. It was the tensioner (new one fixed that). Problem here is a slightly different noise.

Unless its damn coincedence (I doubt) the noise does not occur with the belt off. I had hoped it might be an exhaust leak (nope despited one bolt not tightened due to fitment issues with zzp mid length )..or a stuck vla. No belt no noise, belt.............noise.

 

if its there with the belt and not with out it it has to be a belt driven accessory, try using a stethoscope to isolate it. Have you noticed if its louder with the a/c on vs. Off?

 

I used HP Tuners to command the a/c on and off...no change....so Im ruling out the a/c compressor. Has to be either the idler pulley assembly or tensioner assembly.......dunno but was told by other op in thread that the tensioner arms are problematic?

 

update?

 

Actually made a NEW thread lol.


https://www.cobaltss.net/forums/2-0l...2/#post6249789