Correct 16lb. radiator cap

[skyman51]

Can anyone describe numbers and markings on a 16lb. radiator cap for a 1963 Dodge? A picture would be even better. While I am on the subject of the cap. I know it acts as a pressure relief valve and when the pressure reaches whatever the cap is rated for it releases. If there is no recovery tank, that release allows fluid to enter the tanks of the radiator and when it cools is sucked back into the system by the pump. I question my cap because it puked fluid down the fan side of the radiator. Shouldn;t the brass center piece on the inside of the cap be spring loaded? Mine is just loose. I assume than the cap needs replaced?

 

[Slantsixdan]

You need some schoolin', because most of what you're guessing about how radiator caps work isn't how they actually work. When the pressure rating is exceeded, coolant flows out the overflow tube connected to the side of the radiator cap seat on the top tank of the radiator. If there is a recovery tank, that's where the overflow coolant goes. If there's none, it winds up on the ground. The cap does not allow or block flow into the tanks of the radiator! Once the thermostat is open, coolant flows from the engine through the upper radiator hose into the top tank, from there downward through the core and into the bottom tank. From the bottom tank it is sucked into the engine through the lower radiator hose by the water pump. No, the brass disc in the middle of the bottom of the cap should not be spring-loaded.

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