At 11:20 PM 4/22/2010, Tobias Gogolin wrote:
>A tempting thought was also to have a permanent raised refill reservoir,
>just concerned that consistent pressure could cause coolant to squeeze into
>the motor where it doesn't belong!

No need -- the pressure tank purges air when it's hot, and draws back
coolant from the reservoir as it cools off.  It takes around 13 psi
to open the purge valve, but probably less than a pound to open the
inlet valve.

Yrs,
d