I have a 57 olds that the top of the radiator started to leak, I pulled the radiator and had it gone thru now when it is reinstalled it pushes water out the over flow. I have 15 pound cap. With out the cap on the water is moving real well over the tubes. I would think it was the cap, but is not that old I also replaced the theromstat . What do you think?


SID

 

Are you filling the radiator to the top of the filler neck, or are you leaving a couple inches airspace for expansion? If it's overfilled it will puke out coolant till it finds the level it wants, usually 1-2 inches below the neck.

If you know a shop with a cooling system test kit they should be able to test the pressure cap, but if cap was performing properly before a radiator rebuild ought not have affected it.

 

Nice looking 57, I installed an after market overflow tube style tank. Now I don't have that problem anymore. Otherwise Rocketradier is correct leave room for expansion