The "212" represents "too hot" on a zero pressure cooling system. If a pressure cap is used, the boiling point increases 3 degrees for each pound of pressure, so a 4 lb. system boils at 224 degrees, a 7# system boils at 233, etc. All the above temps represent the boiling point at sea level- - - - -coolant boils at lower temps as altitude increases.
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!