I know this sounds weird but I would almost say that Tom was having an
electrical problem.  The only thing electrical in the engine compartment on
the diesel that could be causing a warm, no start would be the solenoid on
the fuel pump.  Perhaps this solenoid is marginal (or the wiring to it is)
and the heat bumps it over the edge to where it won't work properly?
You could try this experiment.  Remove the solenoid and take the shuttle
valve that is inside, out.  This will allow the motor to run but not shut off
(you will have to stall it with the transmission to get it to stop).  Then
run the van and see if you experience your hot start problem.  If not then
you have narrowed it down.

Hope this helps,
Ken Wilford
http://www.vanagain.com
John 3:16
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