Passat PD115 starting problems

[TSS]

On start up the engine revs to nearly 3 thou then drops back to normal after a few seconds, but sounds if the pistons are coming out the top and rattly, only happens when its been sat for a good few hours or from cold. Any ideas? :?  :?  :?

[jtanguay]

blown glowplugs?

[jimfoo]

Leaking oil, valve seals maybe? Do you get a puff of blue smoke when you let off the throttle?