[Rick Yeager]

What should the difference in temperature readings with an Infra Red Thermometer when the termperature from the lower hose is subtracted from the the temperature of the upper hose on a good running radiator? I read one place that it should be above 40 degree F but this seems a little small to me. If this were known, one could readily know if the radiator was the major problem after the engine was warmed up and the fan running. What do you all think?

Thanks, Rick