[RandyMettler]

Well it is good that you mention this. I have a new Griffin Aluminum radiator with the pressure cap and the relief valve that is supposed to suck fluid back into the radiator when the block cools. Is that considered a modern coolant system? I installed an overflow tube canister because it was pucking fluid out of the overflow tub when the engine got overly hot. I could be wrong, but maybe this is why I am now having fluid seeping out of the head studs when I did not with the original radiator. It was definitely not pressurized.