The engine cooling system uses special liquids based on a mixture of water and ethylene glycol. They have a low freezing point and a high boiling point. In addition, due to the complex of added additives, the coolant prevents corrosion of the channel walls, does not foam, and extends the service life of the coolant pump seal. The volume of coolant in the engine cooling system is 7.8 liters.
The circulation of the coolant in the system is provided by a centrifugal pump installed in the engine cylinder block. The water pump is driven by a toothed timing belt.
Depending on the engine temperature, the coolant in the cooling system can circulate in either a small or a large circle.
The thermostat controls the direction of coolant flow in the engine cooling system.
It has two valves installed - the main one and the additional one (bypass). The main valve controls the circulation of the coolant in a large circle, and the bypass valve in a small circle. The valves are interconnected - when one opens, the second closes and vice versa.
When the engine is cold, the thermostat bypass valve is open and coolant circulates in a small circuit through the cylinder block, cylinder head, bypass valve and coolant pump, as well as the throttle assembly and heater core. The heater core is built into the engine cooling system and is designed to heat the passenger compartment by circulating hot coolant through it.
At a temperature of 85±2°C, the main thermostat valve begins to open, and the bypass valve begins to close, and the coolant circulates for some time
in small and large circles simultaneously. At a temperature of 102°C, the main thermostat valve is fully open, and the bypass valve is closed, and the main flow of coolant passes through the engine radiator, where it is cooled by the oncoming air flow. At the same time, the coolant continues to circulate through the throttle assembly and the heater radiator. When the air flow intensity is insufficient to cool the radiator, the electric fan is turned on. It is installed behind the engine radiator and turns on automatically by a signal from the ECU (electronic control unit) engine.
To compensate for the thermal expansion of the coolant, an expansion tank is installed in the cooling system. The expansion tank cap contains the inlet and outlet valves, which allows maintaining optimal pressure in the system when the coolant is heated, as well as compensating for the vacuum when it cools.
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Engine cooling system: 1 - heater radiator; 2 - coolant drain hose from the heater radiator; 3 - coolant supply hose to the heater radiator; 4 - coolant pump hose; 5 - expansion tank hose; 6 - heater radiator steam outlet hose; 7 - expansion tank; 8 - expansion tank fluid level sensor*; 9 - thermostat; 10 - coolant drain hose from engine radiator; 11— hose for supplying liquid to the throttle assembly; 12 - Engine radiator steam outlet hose; 13 - hose for supplying liquid to the engine radiator; 14 - engine radiator; 15 - radiator drain plug; 16 - Electric fan of the engine radiator; 17 - Coolant pump; 18 - supply pipe to the coolant pump; 19 - coolant drain hose from the throttle assembly
* Installed on vehicle parts.