Water use the water (or antifreeze) as a cooling medium away hot parts of the engine heat to ensure the engine to normal operating temperature. Water cooled bythe water pump, radiator, fan, thermostat, water units and water pipes and other components. Water cooling system in the coolant in the engine's water jackets, absorbing heat temperature of high temperature parts, radiator fan for cooling and airflow in the wind and then cooled into the water jacket coolant pump, circulating cooling. Cooling liquid of cycle way has two species: Dang engine water temperature below 70 ℃ Shi, section temperature device close, cooling liquid flows through pump-water sets-section temperature device bypass tube-pump (not by thermal device), that small cycle, such conducive to engine started Hou temperature quickly rose; Dang engine water temperature over 70 ℃ Shi, section temperature device automatically open, cooling liquid flows through pump-water sets-section temperature device switch valve-radiator-pump, that big cycle, to strengthening cooling effect. Cooling liquid with water softener to reduce deposited scale in the radiator and inner wall of water, affecting heat dissipation. Or in winter in cold regions, to useantifreeze. Standing water cooling systems have secondary packaging (also knownas expansion tank), which communicated with the radiators, when the coolant expands to form steam, overflow through the steam valve on the radiator Cap radiatorsteam and water storage, when cooling liquid cooling shrinkage and may be supplemented by the drainage valve to radiator.