New V8 engine noise when cruising

[biggin]

Hi all,
My truck has developed a high pitched whine.
It seems to only occur in the first 10 or 15km of a trip, then seems to disappear. While cruising, the sound appears when backing off the accellerator slightly when cruising, and disappears when nudging the go pedal a little. Sometimes I can make this happen at stop as well by revving a little, then releasing.
It seems as though it is sucking air or something as the vacuum increases.
Other than this, the motor runs A1.
I don't think I have read about these particular symptoms.
Any thoughs?

[bee utey]

Hi all,
My truck has developed a high pitched whine.
It seems to only occur in the first 10 or 15km of a trip, then seems to disappear. While cruising, the sound appears when backing off the accellerator slightly when cruising, and disappears when nudging the go pedal a little. Sometimes I can make this happen at stop as well by revving a little, then releasing.
It seems as though it is sucking air or something as the vacuum increases.
Other than this, the motor runs A1.
I don't think I have read about these particular symptoms.
Any thoughs?
Vacuum leak, possibly the plenum chamber join. Try to listen when you start the car, open the bonnet, fiddle with the revs, and use a piece of hose as a stethoscope.

[ozscott]

I feel your pain having the same exactly. It's coming from the front of the valley in my case but buggered if I am going to strip it down yet just for a metal gasket change. Bloody annoying though. I have had it for 20000k. Cheers

[biggin]

I feel your pain having the same exactly. It's coming from the front of the valley in my case but buggered if I am going to strip it down yet just for a metal gasket change. Bloody annoying though. I have had it for 20000k. Cheers
It is annoying but only seems to last for 10 or 15 minutes before it disappears. I might live with it for now as long as evrything else is okay.



Vacuum leak, possibly the plenum chamber join. Try to listen when you start the car, open the bonnet, fiddle with the revs, and use a piece of hose as a stethoscope.
Each time I have gotten around to investigating the problem, it disappears. But I will use your method when the planets align.:)

Thanks all!