Cooling System 41 The main purpose of coolant is to transport heat from the hot parts of the engine to the radiator and to protect the cooling system from corrosion. In addition to this, the coolant must: Protect against pitting and cavitation erosion damage of the water pump and cylinder liners. Protect against freezing and boiling. Prevent formation of scale, sludge deposits and clogging. Be harmless to polymer materials and seals in the coolant system. Maintain its liquid properties in cold climates. Coolant should consist of these three components: Clean water. Additives. Antifreeze (Glycol). See the next pages for proper handling, mixtures and specifications.