I don't know about your head ( the vans) or your valves, but if you come out
of this unscathed, CHANGE your timing belt! Nothing kills a diesel faster
than a questionable timing belt. I would say that the one on your van falls
into that catagory. If it were me I would have renewed the timing belt
before I put it back into service. I don't remember where it was I first
heard this wisdom, maybe it was from Jack Ewalds page? Here is what I
remember, VW (at this time) hasn't given a "suggested" time/mileage for
changing the belts on the diesel engines but most concur that it should be
done between 45-60k mile intervals, also anytime the vehicle sits for a
period of approx. 2 years,belt should be replaced before putting vehicle
back into service. I change mine at about 40k for peace of mind or if it
looks like it may be questionable (or by some strange occurance) I should
develope a fuel leak or oil leaks onto the belt) I replace it immediately!
Call me what you will, but you usually don't see  me sitting on the side of
the road , unless I'm helping someone! Hope all goes well for you, keep us
posted! Tom :~)