Closed cooling system with forced coolant circulation and expansion tank. The cooling system consists of a cooling jacket (network of channels inside the cylinder block and cylinder head), radiator, water pump, thermostat, radiator fan, hoses and other components.
The pump is vane, centrifugal type, driven by a V-belt.
Solid fill thermostat that expands when heated (opening valve) and shrinks when cooled (closing valve). Thermostat valve starts to open at target temperature (about 80-84°C). At a temperature of about 95°C, the thermostat valve is fully open.
The radiator cap has two safety valves - steam and vacuum. Steam valve opens to remove steam through the outlet pipe (hose), when the pressure inside the cooling system exceeds the maximum allowable value (coolant temperature 110-120°C, valve opening pressure). Air (vacuum) the valve opens to reduce the vacuum that occurs in the cooling system after the engine has stopped and the temperature has dropped (pressure -7 kPa or less).
Opening the valve allows the coolant to return to the system from the expansion tank.
On vehicles with automatic transmission, a heat exchanger is installed in the lower radiator tank to cool the automatic transmission fluid (ATF).