need i point out that gauge pressure is operative here. for example, with
pressure cap removed and engine off, system is in equilibrium with
atmosphere, and psig is zero at exposed fluid surface, maybe 1 - 2 psig
due to hydrostatic head at lowest places. in operation, system at 15 psig
has absolute pressure of 2 atmospheres, or about 30 psi. stress on system
is indicated by psig: a totally flat tire always has psig = 0, but psi =
atmospheric pressure.

dlk

On Tue, 2 Mar 2004 22:17:32 -0500, David Brodbeck <gull@GULL.US> wrote:

>On Tue, 2 Mar 2004, Daniel L. Katz wrote:
>
>> also, this would be very safe for the cooling system, in terms of
>> working at or below atmospheric pressure.
>
>If 15 psi isn't "safe" for your cooling system, I think you want to find
>that out before you get out on the road. ;)