Original sentence: Most internal combustion engines are fluid cooled using either air (a gaseous fluid) or a liquid coolant run through a heat exchanger (radiator) cooled by air
Edited sentence: Fluid cooled  engines have  a circulation pump which insures that  the temperatures of the coolant are   within close limits throughout the engine block.Internal combustion engines are fluid cooled using either air (a gaseous fluid) or a liquid coolant run through a heat exchanger (radiator) cooled by air.This will prevent the occurrence of hot spots , which are more likely to be present  with air cooling.Turbocharged  engines frequently have  additional oil sprayed on the bottom of the piston for extra cooling