Posted by Sean on Sunday, February 17, 2002 at 9:30PM :
This came up last forum? Or maybe two forums ago?
Anywho, the punchline is that, as your probably aware there were two types of radiator caps, and
"Radiators of all vehicles covered by this manual are equipped with PRESSURE CONTROL radiator caps...The radiator cap is equipped with a spring loaded valve that seals the overflow pipe opening from the radiator proper, when the correct cap is installed with THE GASKET IN THE RADIATOR FILLER NECK. The spring loaded valve must be tight against the gasket to seal the cooling system." (emphasis mine)
So it would seem that the gasket is a separate piece, not part of the cap, and that it is installed in the radiator neck.
It goes on further to state "The valve in the cap remains on its seat until the pressure in the cooling system exceeds 1.5 to 2.5 pounds per square inch."
Not much pressure at all by todays standards.
continuing the paragraph "Whenever the cooling system is filled or a vehicle inspected, note the condition of the gasket and tighten cap securely. Replace the gasket whenever it becomes warped or when the valve is not making complete contact witht the gasket.
Anywho, hope this helps whoever it was that asked...
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