Okay,

I now know that closing the main valve on the tank does not isolate the
leak source to the tank, filler stuff, or input side of the main valve.
After letting the van sit overnight with the main valve off, I cracked
open a stove burner valve and heard a hiss of gas for a moment. This
suggests that the main valve does not close completely. So the whiff of
propane that I smell from the tank area could be from any part of the
plumbing.

What's the scoop on those valves? Rebuildable? Available for replacement?

I wonder if a valve that does not close completely could also be the
leak source.

--

Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR