[Alaska Jim]

optimum distance between a fan and radiator without a shroud is 3/4 of an inch. if you have a fan shroud, the fan blades should extend only about halfway into the shroud opening. anything other than this will not result in maximum cooling. you may also want to check different sections of your radiator with an infrared heat gun for "cold" spots that may indicate that the radiator is partially plugged. this will cause low speed/idle overheating, but may be ok at speed. note that the bottom of the radiator should be cooler than the top, as the pumps pull the coolant up and into the block and "push" it out the top outlets back into the radiator. unless my mind is thinking backwards. hope that this will help