In a message dated 3/31/01 5:18:03 PM, Trawlertom@AOL.COM writes:

<< the pressurization at first
occurs only sporadically; usually after a prolonged period of driving and
then following a short stop. >>

Thomas,

Why do you say that the coolant system is being pressurized?  Have you tested
it with a pressure gauge or is the coolant filling the coolant reservoir and
coming out of the vent holes on top?  If so, it may be merely a defective
pressure cap on the pressure tank.  If a foreign particle becomes lodged in
the pressure or vacuum valve inside the pressure cap, the coolant system will
not under normal operating pressure and it will "boil over" in the manner you
describe, i.e., after a hard run and intermittently.

Rich