The symptom:
Van steadily gets hot upto about 7/8 of the temp gauge.  Running both
heaters on full blast while driving at highway speeds brings temp gauge
down to about 3/4.  With the new radiator the flow from the radiator bleed
screw is pretty good.  The radiator fan does'nt come on until the temp
gauge reads about 9/10.

What I've done already:
1.  Flushed system with water by installing flush tee in front heater
return hose.
2.  Replaced Green coolant with Orange Prestone extended life and
bled the system.
3.  Replaced temp gauge sensor twice (thought it might be faulty).
4.  Replaced voltage regulator for temp and fuel gauges w/ new one.
5.  Replaced thermostat with new normal (higher temp) one.
6.  Replaced expansion tank pressure cap.
7.  Tried running without thermostat.  Took a long time to warm up then ran
hot.
8.  Replaced radiator.  Flushed all the coolant out of the system with
water.  Bled system thouroughly.  No more air bubbles from front bleed
screw.  Can't get anymore coolant in at the tank.

Any ideas about what to do next?
How can I tell if my head gaskets are cracked or leaking?
H20 pump is definitley pumping something, maybe not enough?
Any ways to take the temperature of the van using an external thermometer?
How can I tell if my coolant hoses are clogged and where they are clogged?

Many thanks to all who have helped me so far with this problem especially
Ken at Vanagain and Boston Bob Donalds who offered advice on bleeding the
system and all who respond to this one.  I only have a few days left to fix
this problem because I have to move -with or without the van.

Thanks,
Andrew Fox
86 Westfalia GL
508-457-2356
www2.hawaii.edu/~andrewf/vanagon/links.htm