At 07:22 PM 1/18/2007, Tom Salicos wrote...
>If this is what I think it is, it is a material that changes color
>with
>temperature.
>...
>It is most likely that our vans'
>tanks do not flow enough to cause the very cold gas area above the
>liquid.\

One simply has to use Plan B. Pour some warm water over the liquid
crystal indicator. The part of the tank with liquid will absorb the
heat quicker, so there will be a temperature difference at the level of
the liquid, which will be indicated.

How to pour warm water onto a tank mounted under a Westy is an exercise
left to the reader. :-)