In order to ensure that the surface of the cylinder can work properly at high temperatures, the cylinder and cylinder head must be cooled at all times. There are two ways of cooling: one with coolant to cool (water-cooled); the other with air to cool (air-cooled).
Automotive engines are more water-cooled. When the engine is cooled with water, both the cylinder and the cylinder head are filled with coolant cavities, called water jacket, cylinder block and cylinder cover on the water jacket is interconnected.
Engine air cooling, the cylinder block and the outer surface of the cylinder head cast a lot of heat sink to increase the cooling area, to ensure adequate heat dissipation. General air-cooled engine cylinder and crankcase is separately cast
