Can you be a little more specific? Cooling of what, engine coolant, intercooler for turbo/super charger, oil.
If you mean engines in general, just look at the auto market; virtually everyone who was once exclusively air cooled, now offers water cooled engines. (Even motorcycles.) Water cooled engines help guarantee more even cooling for all cylinders which allows running leaner mixtures and higher combustion temperatures with less danger of cooking the hot cylinder(s). About the only thing that hasn't gone this way, for obvious reasons, are aircraft. IMHO, of course.
