The system is filled with ethylene glycol based liquid (antifreeze), non-freezing at ambient temperatures down to –40°C.
Note: The procedure for replacing the coolant is described in the subsection "Replacing the coolant".
Warning! It is not recommended to fill the cooling system with water, as the antifreeze contains anti-corrosion and anti-foaming additives, as well as additives that prevent scale deposition.
Coolant is toxic! Avoid inhaling its vapors and contact with skin.
Repair leaks in the cooling system promptly to avoid coolant vapors getting into the car's interior during operation. Your health is more valuable than a new cooling system hose or a tube of sealant!
In addition to the radiator, water pump, expansion tank and hoses, the system includes a cast engine cooling jacket surrounding the cylinder walls in the block, combustion chambers and gas passages in the cylinder head, as well as a radiator for the vehicle's interior heater.
The normal thermal mode of the engine is determined by the temperature of the coolant, which is maintained automatically by a thermostat in the range of 90–100°C.
Radiator with horizontal liquid flow, with tubular-ribbon aluminum core and plastic tanks. The left tank contains the supply and discharge hoses to the engine water jacket.
The expansion tank serves to compensate for the changing volume of the coolant depending on its temperature. It is made of translucent plastic. Its walls are marked with "MAX" and "MIN" to control the coolant level; at the top there is a filler neck, hermetically sealed with a plastic plug with two valves inside it (inlet and outlet), assembled in a single block. The outlet valve opens at a pressure of (140±10) kPa or (1.4±0.1) kgf/cm², ensuring an increase in the boiling point of the coolant and preventing intensive vaporization. When the liquid cools, its volume decreases and a vacuum is created in the system. The inlet valve in the plug opens at a vacuum of about 10 kPa (0.1 kgf/cm²) and allows air to pass into the expansion tank.
Note: The correct operation of the plug valves is very important for the normal operation of the cooling system. However, when problems occur, they often (boiling of coolant, etc.) car enthusiasts pay attention only to the operation of the thermostat and forget to check the valves. A leaky exhaust valve leads to a decrease in the boiling point of the coolant, and its jamming in the closed state leads to an emergency increase in pressure in the system, which can cause damage to the radiator and hoses.
The centrifugal water pump provides forced circulation of liquid in the cooling system, is mounted on the front surface of the cylinder block and is driven by a toothed timing belt. The pump has sealed bearings that do not require replenishment of lubricant. The pump is not subject to repair, therefore, in case of failure (fluid leak or bearing damage) it is replaced as a whole.
A thermostat with a solid temperature-sensitive filler maintains the normal operating temperature of the coolant and reduces the engine warm-up time. It is installed on the rear end of the cylinder head. At a coolant temperature of up to 88°C, the thermostat is completely closed and the liquid circulates along a small circuit, bypassing the radiator, which accelerates engine warm-up. At a temperature of 89°C, the thermostat begins to open, and at (99±2)°C it opens completely, ensuring the circulation of liquid through the radiator.
An electric fan with a plastic six-blade asymmetric impeller provides air flow through the radiator at low vehicle speeds, mainly in urban conditions or on mountain roads, when the oncoming air flow is insufficient to cool the radiator.
To improve efficiency, the fan is mounted in a casing and attached to it at three points. The casing, in turn, is attached to the radiator at four points.
The electric fan is controlled by the engine control unit, which receives information about the coolant temperature from a sensor located in the water jacket of the engine cylinder head.