[cman46]

The problem is called Cavitation. Most Cobra and Street Rod radiators do not have expansion tanks. With the typical cap designed for overflow recovery no expansion tank means water out, air in. I do not choose to debate all the types of recovery tanks so let's just keep it simple. Coolant out when hot feeding the bottom of a tank of some sort. The tank should be even with or a tick higher than the filler cap entry. That way coolant in from the bottom and as it cools, flow is assured and no air. Engineering is up to the owner. That is my story and I am sticking to it. Colin