Haulin_in_Dixie

Also you better watch the freeze level in the summer time or you will have a frozen and leaking heater core. Needs to be protected down to about 10 degrees even in the summer. If you have had the experience of changing a heater core, you are very careful about this, I promise

RowJ

Bill - Is it the antifreeze...or the pressurizes system that does the most to allow higher temps?
I don't really know...have always wondered.

HID - That's a great point....and one of the reasons for 25% antifreeze, which I believe is good down to about 0*.

RJ

infidel

Boiling temp vs cap pressure

0 psi - 212°F

5 - 227

10- 240

15- 250

20 - 259

25 - 267

Antifreeze also raises the boiling point, it usually says by how much right on the jug

Timmay2

antifreeze is also needed to prevent corrosion and keep the water pump lubricated....