At 06:56 PM 5/10/2016, John Rodgers wrote:
>something goes wrong in the system. But it would be interesting to know
>what the actual system pressure range is, especially since sea level
>atmospheric pressure is 14.7 psi.

It's 14.7 psi absolute or 0 psi gauge pressure, all depends on where
you take your reference from.

>That weight of air is enough to push the
>coolant back in to the system as the coolant cools and shrinks. So what is
>actual system pressure at both ends of the spectrum - hot and cold?

The pressure cap opens for outflow around 13-15 psig and for inflow
at much lower pressure, less than one psi I think -- you can make it
open with your breath.

Yrs,
d