[Simon Bailey]

Hi all,

I've just picked up an 03 XC90 D5 with 160,000 on it. It has a full history and the timing belt was done in Dec 2014.

It has just started to make a knocking noise when accelerating, very similiar sound to pre-ignition. Easing off the throttle will make the noise go away. The noise is not reproducible when not driving or by holding the brake and revving the engine in Drive. The frequency of the knocking is engine speed related, not vehicle speed related.

I have a Haynes manual, but no diagnostics kit and I am fairly handy with a spanner (many years of rebuilding and racing classic cars and bikes).

I've got the following on my suspect list, after spending hours googling...

1) Engine mounts, including strut brace.
2) Alternator pulley clutch
3) Knock sensor
4) Check that the timing belt was fitted correctly

With regards to the Engine mounts, I have to say that there is what I would consider to be a lot of slop in the upper mount and strut brace - The square top bush has a 2-3 mm gap between itself and the housing, and the strut brace can move for and aft by approx 1"-2". Is this normal?

Any help in solving this would be greatly appreciated.

Simon