Overheating headache

My post #14. Yes, what I said about limiting AF for your climate will ensure best cooling & transfer of heat from the coolant to the rad core.
Pure water boils at 212*. With a 16 lb rad cap, the b/point is raised to 260*. If you need a BP higher than 260, then you have other problems.....
Some people confuse AF with rust inhibitor, two different things.