The Volkswagen air-cooled engine is an air-cooled, gasoline-fuelled, boxer engine with four horizontally opposed cast-iron cylinders, cast aluminum alloy cylinder heads and pistons, magnesium-alloy crankcase, and forged steel crankshaft and connecting rods.

Air-cooled engines rely on the circulation of air directly over heat dissipation fins or hot areas of the engine to cool them in order to keep the engine within operating temperatures. Air-cooled designs are far simpler than their liquid-cooled counterparts, which require a separate radiator, coolant reservoir, piping and pumps.