The system is filled with ethylene glycol based coolant (antifreeze), non-freezing at ambient temperatures down to –40°C.
Figure 5.16. Location of cooling system elements: 1 – expansion tank; 2 – heater hoses; 3 – thermostat; 4 – coolant temperature gauge sensor (not visible in the photo, located under the thermostat); 5 – coolant temperature sensor; 6 – radiator hoses; 7 – radiator drain plug; 8 – cylinder block drain plug; 9 – throttle body heating hoses
The arrangement of the cooling system elements is shown in the figure 5.16.
Note: The procedure for replacing the coolant is described at the beginning of the section. 4 "Maintenance".
Attention! It is not recommended to fill the cooling system with water, since the antifreeze contains anti-corrosion and anti-foaming additives, as well as additives that prevent scale deposition.
Warning! Coolant is toxic! Avoid inhalation of vapors and skin contact.
Warning! Promptly eliminate leaks in the cooling system to prevent coolant vapors from entering the vehicle interior during operation. Your health is more valuable than a new cooling system hose or a tube of sealant!
Figure 5.17. Cooling system: 1 – expansion tank; 2 – expansion tank cap; 3 – radiator drain hose; 4 – engine cooling system radiator; 5 – Engine management system coolant temperature sensor; 6 – radiator supply hose; 7 – thermostat; 8 – coolant temperature indicator sensor; 9 – thermostat gasket; 10 – cylinder head; 11 – water pump gasket; 12 – water pump; 13 – laying the supply pipe; 14 – water pump inlet pipe; 15 – filling hose; 16 – hose from thermostat to water pump inlet pipe
The design of the cooling system is shown in the figure 5.17.
Water pump 12 (see figure 5.17) centrifugal type provides forced circulation of liquid in the cooling system, is installed on the front plane of the cylinder block and is driven by a toothed belt of the camshaft drive. The pump is equipped with sealed bearings that do not require replenishment of lubricant. The pump cannot be repaired in case of failure (fluid leak or bearing damage) it is replaced as a whole.
Thermostat 7 with solid temperature-sensitive filler maintains normal operating temperature of the coolant and reduces engine warm-up time. It has a primary and secondary (bypass) valves. At a coolant temperature of up to (85±2)°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 (85±2)°C the thermostat begins to open, and at 102°C it opens completely, ensuring circulation of liquid through the radiator.
Electric fan 15 (figure 5.18) with a plastic four-blade impeller provides air blowing 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 the efficiency of the fan, it is installed in the casing 8 and attached to it at three points through rubber cushions. The casing, in turn, is attached to the radiator 4 at four points.
The electric fan is controlled by the engine control unit, which receives information about the coolant temperature from sensor 5 (see figure 5.17), located in the thermostat socket 7.
Figure 5.18. Radiator with electric fan and expansion tank: 1 – expansion tank; 2 – heater radiator steam outlet hose; 3 – steam outlet hose of the cooling system radiator; 4 – radiator; 5 – drain plug; 6 – drain plug sealing ring; 7 – radiator support cushion; 8 – electric fan casing; 9 – elastic bushing; 10 – spacer sleeve; 11 – washer; 12 – spring washer; 13 – nut; 14 – bolt; 15 – electric fan; 16 – expansion tank cap
Radiator 4 (see figure 5.18) tubular-plate, aluminum, with plastic tanks, two-way, with a partition in the left tank. At the bottom of the right tank there is a drain plug 5. The tanks contain the supply and return hose pipes to the engine water jacket and the hose pipe connecting the radiator to the expansion tank.
Expansion tank 1 serves to compensate for the changing volume of coolant depending on its temperature. The tank is made of translucent plastic. On its walls there are marks "MAX" and "MIN" for monitoring the level of the coolant, on top there is a filler neck, hermetically sealed with a plastic plug 16 with two valves inside it (inlet and outlet), collected in a single block. The outlet valve opens at a pressure of 110 kPa (1.1 kgf/cm²), ensuring an increase in the boiling point of the coolant and preventing intensive vaporization. When a 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 3 kPa (0.03 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, but often when problems occur (boiling of coolant, etc.) car enthusiasts pay attention only to the operation of the thermostat, forgetting to check the valves. A leaky outlet valve will cause the boiling point of the coolant to drop, and if it gets stuck in the closed position, it will cause an emergency increase in pressure in the system, which can cause damage to the radiator and hoses.
The interior heater radiator is connected to the cooling system via hoses.
Possible malfunctions of the cooling system, their causes and solutions are given in the table.