Cooling system: 1 - outlet hose of the radiator; 2 - radiator of the cooling system; 3 - steam outlet hose; 4 - electric fan; 5 - radiator inlet hose; 6 - thermostat cover; 7 - hose for supplying fluid to the heating unit of the throttle assembly; 8 - hose for draining fluid from the heating unit of the throttle assembly; 9 - inlet hose of the heater radiator; 10 - outlet hose of the heater radiator; 11 - inlet hose; 12 - expansion tank; 13 - inlet pipe of the pump of the cooling system.
The cooling system is liquid, closed type, with forced circulation. It consists of an expansion tank, a coolant pump, an engine cooling jacket, a thermostat, connecting hoses and a radiator with an electric fan. The heater core is connected to the cooling system. The system is filled with coolant through the neck of the expansion tank.
The expansion tank is made of translucent plastic, which allows you to visually control the coolant level. On the wall of the expansion tank there are marks MAX and MIN, between which there should be a liquid level on a cold engine.
A steam outlet hose is connected to the upper branch pipe of the tank, connecting the tank to the radiator, and a hose for draining fluid from the throttle assembly heating unit is connected to the middle branch pipe. The lower branch pipe of the tank is connected by a filling hose to the inlet pipe of the pump.
The tightness of the cooling system is ensured by inlet and outlet valves in the cap of the expansion tank.
If the cover is lost, it cannot be replaced with a sealed cover without valves, even of a suitable size and thread, as this will lead to an unacceptable increase in pressure in the cooling system (on a hot engine) and as a result - leakage of coolant from under the hose clamps.
The circulation of liquid in the cooling system is provided by a coolant pump. The coolant pump is a vane, centrifugal type, driven by a toothed timing belt.
coolant pump
The liquid enters the pump through a supply pipe located on the rear wall of the cylinder block under the intake manifold. From the pump, liquid under pressure is supplied to the engine cooling jacket, and from there to the pipe of the cylinder head, on which the thermostat is installed.
On a cold engine, the thermostat valve is closed and shuts off the outlet pipe of the thermostat housing cover leading to the radiator of the cooling system. In this case, all the liquid circulates through the engine cooling jacket. Part of the liquid from the cooling jacket through a hose connected to the branch pipe of the block head enters the heater radiator, and then returns to the pump. The fluid enters the throttle assembly heating unit through a hose connected to the fitting of the thermostat housing, and from there into the expansion tank and then returns to the pump.
In this case, the liquid circulates in a small circle.
Thermostat
As the engine warms up, at a fluid temperature of 87°C, the thermostat valve begins to move, opening the thermostat cover outlet and allowing fluid to flow into the cooling system radiator. At a temperature of 102°C, the thermostat valve opens completely and the liquid enters the radiator of the cooling system, where it gives off heat to the surrounding air. The movement of fluid through the engine cooling jacket and the cooling system radiator forms a large circulation circle. The thermostat valve closes at a liquid temperature of 86°C. Through the heating unit of the throttle assembly and the heater radiator, the liquid circulates constantly and does not depend on the position of the thermostat valve.
Radiator with fan assembly: 1 - lower radiator tank; 2 - outlet pipe of the radiator; 3 - fan casing; 4 - fan motor; 5 - steam outlet pipe of the radiator; 6 - fan impeller; 7 - inlet pipe of the radiator; 8 - the upper tank of the radiator; 9 - drain plug
The radiator of the cooling system consists of two horizontally located plastic tanks connected by aluminum tubes with cooling plates arranged in one row.
The liquid enters the radiator through the pipe of the upper tank, and is discharged through the pipe of the lower tank. To drain the coolant there is a drain hole closed with a plug.
The electric fan is installed in a casing behind the radiator.
Fan with shroud assembly:
On vehicles with an air conditioning system, two fans can be installed - a main and an additional one.
The work of the main and additional (if available) fans are controlled by an electronic control unit (ECU) motor, which, through the corresponding relay, ensures the rotation of the fan impeller at two speeds. The ECU turns on the main fan at low speed at a coolant temperature of 93°C - for engines 1.8 or at 97.5°C - for engines 1.4 and 1.6 and at high speed at 97°C - for engines 1, 8 or at 101.25°С - for motors 1.4 and 1.6, switches the fan from high speed to low at 94°С - for motors 1.8 or at 99°С - for motors 1.4 and 1, 6 and turns it off at 90°C - for engines 1.8 or at 95.25°C - for engines 1.4 and 1.6.
The additional fan is turned on by the computer at a low speed when the air conditioning system is turned on, and at a high speed when the coolant temperature is above 97°C or when the pressure in the air conditioner discharge line reaches 1859 kPa.
High fan speed turns on the high fan speed relay.
For vehicles with two fans, the main fan low speed is activated by the low fan speed relay, and the secondary fan low speed by the fan control relay.
For vehicles with a single fan, an additional resistor is added to the low speed fan circuit after the low speed relay.
Fan Low Speed Resistor
There is no coolant temperature gauge in the cooling system. Information on the coolant temperature gauge comes from the coolant temperature sensor used in the engine management system.