1. Outlet (to the pump). 2. Spigot (to expansion tank). 3. Thermostat cover. 4. Main valve spring. 5. Bypass valve spring. 6. Inlet pipe (from the radiator). 7. Main valve. 8. Thermostat housing. 9. Bypass valve. 10. Inlet pipe (from the engine). 11. Piston. 12. Rubber insert. 13. Thermally sensitive solid filler. 14. Cylinder head outlet. 15. Hose from the radiator. 16. Pipe (to interior heater). 17. Hose for supplying fluid to the pump. 18. Thermostat. 19. Expansion tank. 20. Hose to radiator. 21. Left radiator tank. 22. Electric motor. 23. Fan impeller. 24. Radiator core. 25. Sensor for turning on the electric fan. 26. Coolant temperature indicator sensor. 27. Fluid outlet hose from the intake pipe heating. 28. Tube to the pump. 29. Lower radiator support. 30. Drain plug. 31. Fan cover. 32. Pump impeller. 33. Oil seal. 34. Bearing lock screw. 35. Bearing. 36. Toothed pulley. 37. Pump roller. 38. Thrust sealing ring of the stuffing box. 39. Graduation (steam) valve. 40. Inlet valve. 41. Outlet pipe of the heater of the passenger compartment. 42. Coolant pump.
Engine cooling system - liquid, closed type, with forced circulation of liquid, with expansion tank 19. The cooling system includes the following elements: coolant pump 42, cooling jackets for the block and cylinder head, non-separable thermostat 18, radiator with expansion tank 19, electric fan, drain plugs, pipelines and hoses.
When the engine is running, the liquid heated in the cooling jackets enters through the outlet pipe 14 through hoses 20 and 17, respectively, into the radiator or thermostat, depending on the position of the thermostat valves. Next, the coolant is sucked in by the pump 42 through the inlet pipe 28 and fed back into the cooling jacket. Hose 27 circulates liquid and heats the combustible mixture in the intake pipe.
The cooling system uses liquid Tosol-A40. which does not freeze when the temperature drops to -40°C and excludes the formation of scale in the system. The fluid is an ethylene glycol mixture with anti-corrosion and anti-foam additives. The density of the coolant Tosol-A40M is 1.078... 1.085 g / cm3. With a decrease in the density of the liquid, Tosol-A liquid is used to restore it.
The capacity of the cooling system, including the interior heater. is 4.8 liters.
Checking the filling of the system with coolant is carried out on a cold engine (+15...+20°С) according to the liquid level in the expansion tank, which should be 25... 30 mm above the mark «MIN». The translucent expansion tank allows you to visually control the level. If necessary, the liquid is added through the filler neck of the expansion tank.
To control the temperature of the coolant, there is a sensor 26 installed in the cylinder head, and a pointer to the instrument cluster in the passenger compartment. The temperature of the liquid in the cooling system of a warm engine at an ambient temperature of 20... 30°C with full load and when driving at a speed of 80 km / h should not exceed 95°C.
In the normal thermal mode of the engine, the pointer needle is at the beginning of the red field of the scale. The transition of the arrow to the red zone of the scale indicates an increased thermal condition of the engine, which may be caused by malfunctions in the cooling system (insufficient amount of coolant, malfunction of the thermostat or electric fan), and difficult road conditions.
The fluid is drained from the system through drain holes closed with plugs: one at the bottom of the right radiator tank, the other - in the cylinder block from the radiator side.
The car interior heater is connected to the cooling system. The heated liquid from the cylinder head enters through the inlet pipe 16, hoses and the heater tap, and is sucked off by the pump 42 through the hose and outlet pipe 41.
Coolant pump
The coolant pump is a centrifugal type, driven by a toothed camshaft drive belt.
Pump 42 is bolted to the cylinder block from the front through a gasket.
The pump housing is made of aluminum alloy. A roller 37 is installed in the housing in a double-row ball bearing 35. The bearing is locked with a screw 34. To prevent the screw from loosening, the contours of the screw seat are chiselled after assembly. The role of the inner race of the ball bearing is performed by the pump roller. During assembly, the cavity of the ball bearing is filled with Litol-24 grease for the entire life of the engine.
On the roller 37, on the one hand, a cast-iron impeller 32 is pressed, and on the other, a toothed pulley 36, made of a ceramic-metal composition. Each time the pulley is removed from the roller, it is recommended to replace it with a new one so that the pulley cannot rotate on the roller when it is reinstalled.
To the end face of the impeller 32, hardened by high-frequency currents to a depth of 2...3 mm, the sealing ring 38 of the stuffing box 33 is pressed. The ring is made of a graphite composition.
Stuffing box 33 is non-separable, consists of an outer brass cage, a rubber cuff and a spring, it is pressed into the pump casing. The stuffing box seals the roller 37 of the pump. In the event that coolant passes through a damaged oil seal, there is a drain hole in the housing under the bearing to drain it.
To remove the axial load on the roller and ball bearing during pump operation, two through holes are made in the impeller from the discharge cavity side, which connect the cavities on one and the other side of the impeller, equalizing the pressure of the coolant in these cavities.
The pump assembly is interchangeable with the pump of the VAZ-2108 car.
Radiator and expansion tank
The radiator is collapsible, with plastic tanks, tubular-plate, with two rows of tubes.
The core 24 of the radiator consists of 36 aluminum round tubes and aluminum heat transfer plates of tube fins, the core is attached to plastic tanks through rubber seals. To increase the efficiency of liquid cooling, the cooling fins are stamped with a notch that provides turbulent air movement through the radiator. The radiator is two-way, the left tank has a partition dividing it in half.
The use of aluminum and plastic in the manufacture of the radiator significantly reduced its weight.
The radiator does not have a filler neck, the liquid is poured into the expansion tank. The upper branch pipe of the left tank 21 of the radiator is connected by a hose to the expansion tank 19. The left tank also has inlet and outlet pipes. The right radiator tank has a drain plug 30 and a sensor 25 for turning on the electric fan.
The radiator assembly is mounted on three rubber supports: two at the bottom are inserted into the holes in the front of the body, the third at the top is pressed by a plate with two nuts. Rubber core gaskets and rubber mounts dramatically reduce the impact of vibration loads on the radiator.
Expansion tank 19 is made of translucent polypropylene, fastened with a belt to the brackets of the front body shield. The lower branch pipe of the expansion tank is connected by a hose to the thermostat 18. To prevent the formation of vapor locks in the cooling system, the upper branch pipe of the tank is connected by a hose to the left tank 21 of the radiator.
The expansion tank has a filler neck closed with a plastic stopper with an outlet (steam) 39 and inlet 40 valves. The valves are installed in the plug in a separate non-separable brass block.
The plug is interchangeable with the plug of the expansion tank of the VAZ-2108 car.
On a running engine, with a sharp increase in the temperature of the coolant or its boiling, the pressure and heat transfer of the radiator increase. When the pressure rises to 1.1 kgf/cm2 graduation opens (steam) valve 39, and the vapors leave the tank to the atmosphere.
When the liquid in the system is cooled or the liquid is drained, the pressure in the system decreases and atmospheric air is sucked into the system through the inlet valve 40. The pressure of the beginning of the opening of the inlet valve is 0.03... 0.13 kgf / cm2. To completely drain the fluid from the system, the plug of the expansion tank must be removed.
Electric fan
The impeller 23 of the fan is four-blade, made of plastic. The impeller blades have a twist angle variable along the radius and a variable angular pitch along the hub to reduce noise. The fan impeller is mounted on the motor shaft 22 and pressed with a nut. For better efficiency, the impeller is located in the casing 31, which is bolted to the radiator nuts.
The electric motor assembly with the impeller is mounted on three rubber bushings and fastened with nuts to the studs of the fan casing 31.
The electric fan is turned on and off automatically depending on the temperature of the coolant using a TM-108 type sensor 25 installed in the right radiator tank. The temperature of closing the sensor contacts should be within 96...102°C, and opening within 91...97°C.
The electric fan is interchangeable with the electric fan of the VAZ-2106 car.
Thermostat and cooling system operation
The thermostat of the cooling system accelerates the warm-up of the engine and maintains the required thermal regime of the engine. Under optimal thermal conditions, the temperature of the coolant should be 85... 95°C.
The thermostat 18 consists of a body 8 and a cover 3, which are rolled together with the seat of the main valve 7. The thermostat has an inlet pipe 6 for the coolant inlet from the radiator, a bypass hose pipe 10 for bypassing liquid from the cylinder head to the thermostat, a pipe 1 for supplying coolant to the pump and pipe 2 hoses to the expansion tank.
The main valve 7 is installed in the thermoelement cup, in which the rubber insert 12 is rolled. The rubber insert contains a polished steel piston 11, fixed on a fixed holder. A heat-sensitive solid filler is placed between the walls of the glass and the rubber insert. The main valve 7 is pressed against the seat by spring 4. Two posts are fixed on the valve, on which a bypass valve 9 is installed, which is pressed by spring 5.
The thermostat is interchangeable with the thermostat of the VAZ-2108 car.
The thermostat, depending on the temperature of the coolant, automatically turns on or off the radiator of the cooling system and bypasses the liquid either through the radiator or bypassing it.
On a cold engine, at a coolant temperature below 87°C, the main valve 7 of the thermostat is closed, the bypass valve 9 is open. In this case, the liquid circulates through the bypass valve 9 through the hose 17 and the supply pipe 28 to the pump 42, bypassing the radiator (in a small circle). This ensures that the engine warms up quickly.
If the liquid temperature exceeds 102°C, the temperature-sensitive thermostat filler expands, compresses the rubber insert 12 and squeezes out the piston 11, moving the main valve 7 to full opening. Bypass valve 9 closes completely. The liquid in this case circulates in a large circle: from the cooling jacket through hose 20 to the radiator and then through hose 15 through the main valve 7 and pipe 1 enters the pump, which is again sent to the cooling jacket.
In the temperature range of 87... 102°C, the thermostat valves are in intermediate positions, and the coolant circulates in small and large circles. The opening value of the main valve ensures gradual mixing of the liquid cooled in the radiator, which achieves the best thermal regime of the engine.
The temperature at which the main valve of the thermostat begins to open should be within 85...95°C, and the stroke of the main valve should be at least 8 mm when the temperature rises to 102°C.
Checking the beginning of the opening of the main valve is carried out in a tank with technical glycerin. The initial temperature of glycerin should be 78...80°C. The temperature of glycerin is gradually increased by 1°C per minute. The temperature at which the stroke of the main valve is 0.1 mm is taken as the temperature at which the valve opens.
The simplest test of the thermostat can be carried out by touch directly on the car. With a working thermostat, after starting a cold engine, the lower hose 15 begins to heat up when the arrow of the fluid temperature gauge on the instrument cluster is approximately 3... 4 mm from the red zone of the indicator scale.