Vx Series 2 Ecotec Engine Bay Noise

[Hot-Rod]

Hi everyone. Just recently had a S/C installed. Since the install i have had a strange high pitched noise occur. I am guessing it might be a pulley on it's last legs.

Need second opinion on this, i've searched for pulley related issues on the forum and none of the noises compare to this noise.

Attached is a link to a video of the noise. 28 secs left in the video you can hear the noise start. When the engine is turned off the noise persists for a short period of time before dieing away. The noise disappears under throttle above 1600rpm and returns when rpm falls below this.

Noise from Engine Bay video by holden-bloke - Photobucket

I've already spoken to the S/C manufacture and he is certain the S/C is not the cause.

[sxc_sound]

you could try watching it as someone turns the car off, i was pretty sure that the belt stop spinning pretty much instantly, so you could tell if it was a pulley making the noise after the car is off as the belt stops. Or if the belts stops straight away and something else is making the noise, sounds like you sucked a mouse or something into the intake lol.

[mainpath]

We had that exact same thing happen to our car, it turned out it was one of the pulley, the one where your camera is viewing.
cost $61.50 from holden i think, it sounded exactly the same except the loud sound that your experiencing was only appearing for us when under acceleration.

[VTS5]

Take the belt off,start the engine (dont worry nothing will happen) no noise means S/C OK, one of the pulleys no good.Normally the one under the s/c goes off first very common.Replaced mine about a year ago ($5 from wreckers ).

[Hot-Rod]

I took it around to a mechanic yesterday. He reckons its not a pulley cause the noise continues after the car is switched off????

Can anyone tell me if a pulley would continue to make a noise for a few seconds after the car is off??? Do the bearings continue rotating after the car is switched off or not??

[danja]

Could it just be an air leak in the intake, or something caught in the intake which is acting like a reed when the manifold has negative pressure?

That would explain why it lasts a few seconds after while the pressure equalizes, and when you're on the throttle you'll quickly go to positive pressure with the blower.

[accentstencil]

Could it just be an air leak in the intake, or something caught in the intake which is acting like a reed when the manifold has negative pressure?

That would explain why it lasts a few seconds after while the pressure equalizes, and when you're on the throttle you'll quickly go to positive pressure with the blower.

I agree with this diagnosis. I would be looking for some sort of air leak around the S/C. Definitely not a pulley or the belt.