Rattle at idle 1.9td D8/98

[MJBD8]

In the car doors shut windows closed and just idling I get a loud rattle in the car.
I am Idling at 850Rpm. I have inspected my engine bay and the aux belt isnt bobbing around the sprung tensioner.
The engine mounts are firm as the engine doesnt try and leave the engine bay when clutching in 1st with the hand brake on.
The rattle disapears under load or upping the revs.
Any Ideas guys?

[HimBigChief]

Manifold gasket? I know on the old 1.9 8v petrol engines if the manifold gasket was leaking slightly, or there was a slight crack in the manifold, then you'd get a sort of rattling noise. Alternatively, could a heatshield be loose and vibrating with the rhythm of the car?

[swiss]

Bits of trim need torquing up? The bit covering my sunroof controls rattles a good'n since one of the hooks snapped off and god Araldited back on a bit wonky.