[rotorwrench]

Trucks didn't go very fast as a general rule and they worked harder to pull heavier loads. Cars can cool down pretty well at roads speeds but trucks have to rely on the engine rpm more to draw air through the radiator.

A passenger car or light commercial vehicle should not need a big multi blade fan like that to cool. If it does then it may have radiator tube blockage, a coolant leak, or an engine problem that is adversely affecting it's cooling system.