At 11:37 AM -0800 2/12/2000, Dana Morphew wrote:
>I bought a cheap, unlit, 0-30psi, 1 1/2" gauge from Princess Auto for
>$3.  This was for my Rabbit, but it would work for a Vanagon.
>
>I drilled a hole into my expansion tank above the max. water level and
>close enough to the tank cap to be able to fit a washer and a nut onto
>the silicon caulked threads of a brass, barbed, fitting with a male
>threaded end.  I ran a length of hose through the firewall and attached
>the ends to the barbed fitting and to the gauge, using clamps.  No
>coolant and only air in the line (the gauge is 'air only').
>
>It shows 7psi when I climb the 1/2 mile long, 9% grade hills around here
>and 5psi on the flats at 60mph.  The rad. fan comes on at 10psi and
>turns off at 8psi, so we are not dealing with large pressures.

>-Dana-

This is certainly easy enough sounding. I wonder, however, if the pressures
you are observing are accurate or not. I say this because air is more
easily compressed than liquids and there are 2 different states of matter
here. Any chemists or physicists care to comment?
Later,

Dave C.
Williamsburg, VA
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