The system is filled with ethylene glycol based liquid (antifreeze), which does not freeze at ambient temperatures down to -40°С.
Note. The procedure for replacing the coolant is described in subsection «Coolant replacement».
Warning! It is not recommended to fill the cooling system with water, as antifreeze contains anti-corrosion and anti-foaming additives, as well as additives that prevent scale build-up.
Coolant is toxic! Avoid inhalation of vapors and contact with skin.
Timely eliminate violations of the tightness of the cooling system in order to avoid the ingress of coolant vapor into the vehicle interior during its operation. Your health is more valuable than a new cooling system pipe 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 channels in the block head, as well as a car interior heater radiator.
The normal thermal regime 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 a horizontal liquid flow, with a tubular-ribbon aluminum core and plastic tanks. In the left tank, inlet and outlet pipes of hoses to the engine water jacket are made.
The expansion tank is used to compensate for the changing volume of the coolant depending on its temperature. It is made of translucent plastic. Marked on its walls «MAX» and «MIN» to control the level of the coolant; on top there is a filler neck, hermetically sealed with a plastic stopper with two valves inside it (inlet and outlet), collected in a single block. Exhaust valve opens at pressure (140±10) kPa or (1,4±0,1) kgf/cm2, providing an increase in the temperature of the start of boiling of the coolant and preventing intense vaporization. When the liquid is cooled, 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 lets air into the expansion tank.
Note. The serviceability of plug valves is very important for the normal operation of the cooling system. However, often when problems arise (boiling coolant, etc.) motorists pay attention only to the operation of the thermostat and forget to check the valves. Leakage of the 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 type water pump provides forced circulation of liquid in the cooling system, is installed 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 relubrication. The pump cannot be repaired, therefore, in case of failure (fluid leakage or bearing damage) it is replaced as an assembly.
The solid state thermostat maintains the coolant at normal operating temperature and reduces 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 through 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 opens completely, allowing fluid to circulate through the radiator.
An electric fan with a plastic six-blade asymmetric impeller ensures that the radiator is blown with air at low vehicle speeds, mainly in urban areas or on mountain roads, when the oncoming air flow is not enough to cool the radiator.
To increase the efficiency of the fan is installed in the 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.