A cooling system in an internal combustion engine that is used to maintain the various engine components at temperatures conducive to long life and proper functioning. Gas temperatures in the cylinders may reach 4500°F (2500°C). This is well above the melting point of the engine parts in contact with the gases; therefore it is necessary to control the temperature of the parts, or they will become too weak to carry the stresses resulting from gas pressure. The lubricating oil film on the cylinder wall can fail because of chemical changes at wall temperatures above about 400°F (200°C). Complete loss of power may take place if some spot in the combustion space becomes sufficiently heated to ignite the charge prematurely on the compression stroke.