Disco 2 V8 high pitch scream at idle

Hi all,
As per title I have a horrible high pitch scream that only occurs at idle on my 1999 V8 D2.
My main suspect has been the IAC valve/solenoid (Idle Air Control) and I have removed and cleaned it twice, but the problem still remains.

It's a high pitch scream coming from around the intake manifold somewhere, it goes away when the accelerator is pressed. It's defintely not a tensioner bearing or similar.

I have tried getting a piece of hose, holding it to my ear and trying to find where it's coming from but to no avail. I used throttle body cleaner to clean out the gunk from the IAC and I have also cleaned the throttle body butterfly.

Any help would be appreciated.

Sam

beetroot4000 said:

Hi all,
As per title I have a horrible high pitch scream that only occurs at idle on my 1999 V8 D2.
My main suspect has been the IAC valve/solenoid (Idle Air Control) and I have removed and cleaned it twice, but the problem still remains.

It's a high pitch scream coming from around the intake manifold somewhere, it goes away when the accelerator is pressed. It's defintely not a tensioner bearing or similar.

I have tried getting a piece of hose, holding it to my ear and trying to find where it's coming from but to no avail. I used throttle body cleaner to clean out the gunk from the IAC and I have also cleaned the throttle body butterfly.

Any help would be appreciated.

Sam

Click to expand...

Have you checked security all of the vacuum hoses associated with the manifold/pollution control/air filter, a cracked or insecurely fitted rubber hose could cause such a noise.

Gazbo said:

Have you checked security all of the vacuum hoses associated with the manifold/pollution control/air filter, a cracked or insecurely fitted rubber hose could cause such a noise.

Click to expand...

Check also that the manifold gaskets aren't leaking where they fit against the heads.

H

Gazbo said:

Have you checked security all of the vacuum hoses associated with the manifold/pollution control/air filter, a cracked or insecurely fitted rubber hose could cause such a noise.

Click to expand...

I have looked and haven't found anything obvious.
Other than obvious cracks, whats the best way to check for leaks?
Have seen videos on Youtube of spraying the hoses with carb cleaner and listening for change in engine RPMs?

beetroot4000 said:

H


I have looked and haven't found anything obvious.
Other than obvious cracks, whats the best way to check for leaks?
Have seen videos on Youtube of spraying the hoses with carb cleaner and listening for change in engine RPMs?

Click to expand...

Yep that or Aerostart sprayed about with a bit of caution, as @brian47 has said, check around the inlet manifold gasket.