according to your statements rusty yung radiator...
i suggest ipalinis mo radiator mo sir have it cleaned inside out... then gumamit ka coolant at distilled water.. 60% water / 40% coolant....
isabay mo na din sir ang pag check sa mga hoses mo if meh leak at malutong na..
plus check the thermostat if you have one kung nag fu-full open lift, baka na stuck na yan sa dami kalawang

napapansin at bigyan attention lang cooling system once na cause na ng sakit ng ulo....