Just solve the problem by installing a puke can and pouring the overflow back into the radiator periodically. If the overflow tube is below the level of the liquid in the catch can, it should siphon the coolant back into the radiator every time it cools down.

Or- - - - - -keep beating a dead horse with intellectual exercises about physics!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!