Posted for "Tracy Crook" <lors01@msn.com>:

I see these pressure variations as well.  Things such as ambient temperature, how hard I run the engine, whether or not I push it to the point of nucleate boiling, rate of descent, altitude I was at & so forth.  As long as the coolant is topped off after cool down, everything is OK.  If not, something needs fixing.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com