the auto-stop valve is actually a fill valve. mark is right about them
being hard to come by. when mine went out, i was quoted 250.00 to
replace, and it was doubtful that my local propane folks were going to
find one any cheaper. what i eventually did was replace the oem
auto-start valve with a standard fill valve (available at your local
propane dealer) like the one mark mentioned. (15 bucks in my case)

with the auto-stop valve, there is a line which runs from the valve into
the tank about 3/4 of the way up. if you replace the auto-start with a
standard valve, simply remove the line, and install a stop-cock in the
hole. the stop-cock is opened when you are filling the tank, and when
propane begins shooting out of the stop-cock, your tank is full. simple.

i've had no complaints since i replaced mine. incidentally, the
"carburetor" (?) on my tank was also bad, so i replaced that at the same
time, also with standard propane supplies. total cost, installed* and
filled, $30 bucks.

btw, since then, i found an auto-stop valve in a yard for a steal, i
took it apart and all grommets and seals seemed intact. never been
tested, but i would be happy to sell it for 50 bucks or so.

* if you have the propane people install and test the valves and etc for
you, i would suggest that you go ahead and remove the tank from the van,
and bring it in that way. your propane dealer will like you better for
it, and its a good time to check the tank for rust, and give it a new
coat of paint.

matt greenwell
87glwesty