Radiator building pressure

[Roger S]

Went for a drive last Sun and GN started sputtering and acting strange. Limped home with the engine wanting to stall if given gas. Could only go around 40 mph. Got it to the garage and radiator hose was solid with pressure. After 30 min removed radiator cap and the pressure was unbelievable with fluid spraying everywhere. Motor runs ok at first and water circulating in radiator , no water in oil, heater works , overflow tank is allways full! Bought new radiator cap and problem persists, Car does not seem to get hot! After car runs for 15 min or so it surges and wants to die if given throttle. I need help !! Thanks

 

[novaderrik]

it's supposed to build pressure like that- it raises the boiling point of the coolant and allows it to more efficiently carry the heat away from the engine and radiate it out of the radiator. that's the whole point of the pressure cap- to maintain it's rated pressure in the system.

it's only a problem if it builds up pressure within a couple of minutes of a cold start and boils over- which indicates a blown head gasket that is allowing combustion pressure into the cooling system.

 

[Roger S]

it's supposed to build pressure like that- it raises the boiling point of the coolant and allows it to more efficiently carry the heat away from the engine and radiate it out of the radiator. that's the whole point of the pressure cap- to maintain it's rated pressure in the system.

it's only a problem if it builds up pressure within a couple of minutes of a cold start and boils over- which indicates a blown head gasket that is allowing combustion pressure into the cooling system.

I understand but the cap is 13 psi but there was considerably more pressure than that. Also the overflow tank is allways full and does not seem to flow back in the radiator as it should. The car now will not start ( turns over very slow if at all like it is vapor locked or something. After 10 min or so will start again. The radiator is prob six months old and is a 3 core aluminum job. Car ran great last time I had it out and now this is happening. Any Ideas ? Thanks

 

[1KWIKSIX]

it's supposed to build pressure like that- it raises the boiling point of the coolant and allows it to more efficiently carry the heat away from the engine and radiate it out of the radiator. that's the whole point of the pressure cap- to maintain it's rated pressure in the system.

it's only a problem if it builds up pressure within a couple of minutes of a cold start and boils over- which indicates a blown head gasket that is allowing combustion pressure into the cooling system.

X2
Sounds like a head gasket to me too.