[MBZ] Noisy 300D engine

[Peter Merle]

My one 300D engine ( In Gwagen ) is a lot noisier than the other I have
in a W123 and this really came to a light  when I came agross another
300GD over the weekend and its engine was probably a good 10db quiter
than mine at idle.  My tappets have been checked as has been th
einjection timing. All is well with the engine as far as I know. It
sounds healthy - just noisier that I guess it should be. Sould a bit
like a direct injection truck engine of the 80's . Any thoughts?
PEter