how to diagnose radiator and cooling system function on 93 f-250

if htis is overheating get the truck hot first. then shut it off and unplug electric fans if you have them. then place your hand on different spots on radiator if you feel cold or cooler spots you need another radiator, it should be same temp all over. if fins areloose or corroded/falling out you need another radiator. if the truck heats up as soon as you start it or within 1 /2 minutes check the thermostat.