>>.  The tech let the van idle for about 20 minutes after
I dropped it off while he was fiddling around with his equipment and when he
was ready to hook everything up he noticed coolant leaking out of the rear
part of the engine bay so he immediately shut it off and refused to do any
more with it. <<

If it's overheating at idle the first thing I would check is the cooling
system has been bled of all air. Coolant is not making the rounds from the
front to the back. There is a procedure in the Bentley and probably the
archives for jacking up the front and getting all the air out.  It takes
awhile BTW.

Bryan