Yes, I believe the radiator was the cause of my issues. Although I tryed both combinations of pumps on both radiators and the results were the flowkooler at highway speeds didn't perform as well in both applications.
but the "flowkooler" did was it was designed to do, get money from your wallet into theirs,
I have chased cooling system issues with various cars over the last 40 years and "rarely found" any after-market band aids to do anything more than drain my wallet. in 90 + % of the cases it wound up being the radiator itself.
