Thread: Vac leak driving me insane!

Hi all,

(02 D2 4.0 V8 Manual - owned since new).

The high pitched squeal like a pig is making me insane. Only on backing off and at idle. I have checked all of the usual suspects - vac hoses. No cracks. I have sprayed aerostart around all the hoses and connections. The trouble is that it sounds like it is coming from the plenum behind where the alternator sits....and spraying there does nothing to the revs. I have the same problem with my 95 D1 - although it is only at idle and the sound there is in the same place.

I am beginning to think that the V8's are prone to valley cover gasket failure...is it just me or have others had the screaming banshee under the bonnet?

Cheers

Hey there. My 2003 D2 V8 used to do that. Would not be all the time either. Anyhoo had a problem with coolant leaks. My disco is on gas and has the bypass for gas cooling from about the point where the coolant hoses go through the firewall. There are a couple ot three way sockets in the lines. Well these were completely corroded away.As well as the fitting in the firewall. Replaced these and the squeeling stopped.