The engine cooling system is liquid, sealed with forced circulation. The cooling system includes:
- cooling jackets (head and cylinder block);
- cross-flow aluminum radiator;
- coolant pump;
- thermostat;
- coolant pump drive;
- expansion tank;
- nine-blade fan with soft coupling;
- heat exchanger of the heating and ventilation system, coolant temperature sensor and the coolant itself.
When installing the air conditioner on some car models, an additional electric fan is used.
The pressure for checking the tightness of the cooling system is 1.5 kgf / cm2.
The radiator is designed to remove heat from the coolant and is made in the form of a horizontally located set of aluminum tubes with the right and left tanks. The radiator from the side of the engine is covered with a casing in which the fan is mounted.
The coolant supply hoses are fixed to the radiator pipes with screw clamps. Brackets for fastening the radiator to the body are rubber-metal.
On vehicles with automatic transmission (automatic transmission) The oil cooler is built into the radiator. The working pressure in the automatic transmission system is 8.0 kgf / cm2.
The design of the coolant pump is shown in Figure 5.20.
The coolant pump is centrifugal type, mounted on the front end wall of the engine block. The pump roller is driven by a multi-ribbed belt simultaneously with the generator, the power steering pump (and air conditioning compressor) from the crankshaft pulley. The viscous coupling controls the fan activation. The engines are fitted with a belt «Hutchinson». The drive belt has a size of 5Kx1007, with an air conditioner - 7K-LBx1629. The required belt tension is provided automatically.
Thermostat (7) designed to turn on and off a large circle of engine coolant circulation, depending on its temperature state. The main valve opening temperature is 88±5°С. Full opening temperature of the main valve - 105°C. The full stroke of the main valve disc is 8.0 mm.
Expansion tank (13, see fig. 5.19) serves to fill the system with coolant, a volume that ensures the preservation of the expanding liquid when the temperature rises, and to connect the cooling system with the environment, with an increase or decrease in pressure in the cooling system.
The opening pressure of the pressure reducing valve in the cap of the expansion tank is 1.8–2.1 kgf / cm2. The opening vacuum of the vacuum valve in the plug of the expansion tank is 0.1 kgf/cm2.
The nine-blade fan is mounted on the coolant pump shaft and is designed to create an air flow through the radiator. The fan impeller has a diameter of 420 mm and is connected to the coolant pump drive through a viscous coupling manufactured by «Holset» or «Fichtel und Sachs». The activation and deactivation of the viscous fan clutch depends on the temperature of the engine and on the speed of its crankshaft.
The axial clearance of the viscous coupling rotor is no more than 0.4 mm.
The radial clearance of the viscous coupling rotor is no more than 0.45 mm.
The fan on temperature is 88–96°C, the fan off temperature is 60–65°C.
temperature sensor (4) coolant three-pin, installed on the fitting on the left side of the engine cylinder head. Signals from the sensor are sent to the engine ECU to calculate the required fuel consumption for the required power mode.
The coolant is antifreeze; when replacing it, be sure to flush the cooling system with softened water or special compounds. Let the engine run for 3-5 minutes, drain the water and blow out the system with compressed air.
The capacity of the engine cooling system, including the interior heater, is 12.2 liters. The coolant replacement interval is every 2 years of operation.