high radiator pressure

When I start my 5.7 97 gmc the upper radiator hose seems to have a very high pressure in it until the thermostat opens Is this normal.My cap is new 16lb
and the thermostat is new 190 degree.
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The only prssure you'll have in the system when it's cold is the pump pressure (which is more just the movement of the coolant than real pressure). The cap will regulate the pressure after the system heats up (it's the heating of the coolant that generates the pressure in the system) so I'd only be concerned if you spring a leak that sprays out under pressure.
Group: alt.autos.4x4.chevy-trucks Date: Wed, Mar 22, 2006, 7:24pm From: snipped-for-privacy@tds.net (Gary) When I start my 5.7 97 gmc the upper radiator hose seems to have a very high pressure in it until the thermostat opens Is this normal.My cap is new 16lb and the thermostat is new 190 degree.
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Borrow an actual pressure tester (Stant makes one) and see what you're getting.
If it's truly very high, you might have a blown head gasket.

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