Cooling system: 1 - radiator drain hose; 2 — cooling system radiator; 3 - steam outlet hose; 4 — electric fan; 5 - radiator supply hose; 6 - thermostat cover; 7 — hose for supplying liquid to the throttle assembly heating unit; 8 — hose for draining liquid from the throttle assembly heating unit; 9 — heater radiator supply hose; 10 — heater radiator outlet hose; 11 - filling hose; 12 - expansion tank; 13 — supply pipe of the cooling system pump.
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 radiator 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 MAX and MIN marks, between which the liquid level should be 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 liquid from the throttle assembly heating unit is connected to the middle branch pipe. The lower branch pipe of the tank is connected by a filler hose to the pump inlet pipe.
The tightness of the cooling system is ensured by the inlet and outlet valves in the expansion tank cap.
If the cap is lost, it must not be replaced with a sealed cap without valves, even if it is the right size and thread, as this will lead to an unacceptable increase in pressure in the cooling system (on a hot engine) and as a consequence, coolant leaks from under the hose clamps.
The circulation of liquid in the cooling system is provided by the coolant pump. The coolant pump is a vane, centrifugal type, driven by a toothed timing belt.
Coolant pump
The liquid enters the pump through the supply pipe located on the rear wall of the cylinder block under the intake manifold. From the pump, the liquid under pressure is supplied to the engine cooling jacket, and from there to the cylinder head branch pipe, on which the thermostat is installed.
When the engine is not warmed up, the thermostat valve is closed and blocks 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 goes through a hose connected to the cylinder head pipe to the heater radiator, and then returns to the pump. The liquid goes to the throttle heating unit through a hose connected to the thermostat housing nipple, and from there to 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 outlet pipe of the thermostat cover and allowing the flow of fluid into the radiator of the cooling system. At a temperature of 102°C, the thermostat valve is fully open and the fluid 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 radiator of the cooling system forms a large circulation circle. The thermostat valve closes at a fluid temperature of 86°C. The fluid circulates constantly through the throttle assembly heating unit and the heater radiator and does not depend on the position of the thermostat valve.
Radiator with fan assembly: 1 - lower radiator tank; 2 - radiator outlet pipe; 3 — fan casing; 4 - fan electric motor; 5 — radiator steam outlet pipe; 6 — fan impeller; 7 — radiator inlet pipe; 8 — upper radiator tank; 9 - drain plug
The radiator of the cooling system consists of two horizontally located plastic tanks connected by aluminum tubes with cooling plates located in one row.
The liquid enters the radiator through the branch pipe of the upper tank and is discharged through the branch pipe of the lower tank. There is a drain hole closed with a plug for draining the coolant.
The electric fan is installed in the casing behind the radiator.
Fan with casing assembly:
Cars with air conditioning may be equipped with two fans - main and additional.
The work of the main and additional (if available) the fans are controlled by the engine electronic control unit (ECU), which, via the corresponding relay, ensures rotation of the fan impeller at two speeds. The ECU turns on the main fan at low speed when the coolant temperature is 93°C for 1.8 engines or 97.5°C for 1.4 and 1.6 engines and at high speed at 97°C for 1.8 engines or 101.25°C for 1.4 and 1.6 engines, switches the fan from high speed to low at 94°C for 1.8 engines or 99°C for 1.4 and 1.6 engines and turns it off at 90°C for 1.8 engines or 95.25°C for 1.4 and 1.6 engines.
The additional fan is switched on by the ECU at low speed when the air conditioning system is switched on, and at high speed when the coolant temperature is above 97°C or the pressure in the air conditioner discharge line reaches 1859 kPa.
The high speed fan relay turns on the high speed fan.
On vehicles with dual fans, the low speed of the main fan is controlled by the low speed fan relay, and the low speed of the auxiliary fan is controlled by the fan control relay.
For vehicles with one fan, an additional resistor is added to the low speed fan circuit after the low speed relay.
Low speed fan resistor
There is no coolant temperature gauge sensor in the cooling system. The coolant temperature gauge receives information from the coolant temperature sensor used in the engine management system.