The component parts of any engine must be lubricated or oiled regularly. Lubrication provides a film of oil which reduces the friction that would quickly destroy rubbing parts. The lubricant commonly used is refined from crude oil and is improved with additives that reduce oxidation and corrosion and act as cleaning agents.

In a motor car there is a basin, known as the sump, or oil pan, underneath the engine. This contains the oil which is pumped round the engine while it is running.

The internal combustion engine must also by kept relatively cool. This can be done with air or water. Air-cooling is produced by the pressurized inlet of air into the cooling fins of a cylinder and other parts designed to get rid of excess heat. Water-cooling is produced by water being pumped constantly round the engine from the radiator, which is kept cool by the air stream and by a fan which also works the water-pump.

In winter anti-freeze liquids are added to the engine’s water jacket to prevent it from freezing and damaging the cylinder block.