Hello vanagon gang,
I asked earlier if anyone had actually cleaned the vent of their propane
regulators.  I must assume from the astounding silence that no one has.
Well, now I have and I will report the consequences.  Before I do, however,
I want to say that the people at the gas company say that the vents can
not be cleaned.
The problem is this: I would fill my propane tank ... it would only take
just a bit of propane until it was supposed to be full.  Then it would
only power the fridge for about 3 days or so.  I would then fill again,
and feel like an ideot because it was still full, etc. (Most people would
only  do this once or twice ... I did it about 8 or 9 times).
The solution which seems to work (my fridge has been running now for 8
days) is two fold:
(1) get the propane people to inject methyl alcohol into your system.  This
was mentioned in a posting by Joel about 1 year ago.
(2) After this does not completely solve the problem, here is what I did and
for me, at least, it works:  Go to the car wash and ignore what you are told
about getting water into the vent valve on the regulator.  Really squirt it
good.  This is a desperation move.  Next step: try to dry it as well as 
possible with a paper towel.  Then, go to the drug store and buy a pint of
90% isopropyl alcohol.  Pour and squirt that stuff all over the vent.  The 
hope is that it will dry out the critical areas of the vent.
My results:  my fridge works.
I also bought 2 bottles of 70% isopropyl alcohol to use if the vent freezes
up outside.  I also pour some of the alcohol down the sink after camping to
insure the sink does not freeze.
Stuart Hutton