345 DeSoto
Senior Member
I'm using a 32, four cylinder, zero pressure radiator to cool the blown Hemi in my 32. It cools BEAUTIFULLY whether at prolonged idle, or at consatant highway speed. The problem I had is/was twofold...the cap wasn't seating properly, and the coolant constantly went out the overflow at normal operating temperature. It reached a certain level and stayed constant (just at the level of the overflow tube). But when I shut it off, it would surge from heat soak, and run out more coolant...not much, but enough to constantly have to replace some. What I did to cure it was to dress the sealing surface of the neck as best I could, then add a thin layer of closed cell foam to the sealing surface of the cap. This made the system air tight (except for the overflow tube). I then installed an over flow container and connected it to the outlet of the overflow tube. Problem solved!
I had considered one of George Haney's pressure valves, but it wouldn't have allowed back flow, so I did the closed cooling recovery system. Not an original idea, by far, but it does the trick...