Cooling System Diagram (carbureted engine 1.3 l)
1 - Radiator; 2 - Fan; 3 - Temperature-sensitive sensor-switch; 4 - Outlet pipe; 5 - Water pump; 6 - Cork; 7 - Exit from the inlet pipeline to the carburetor; 8 - Exit from the inlet pipeline to the heater; 9 - Exit from the carburetor; 10 - Heat exchanger of the heater; 11 - Heater fan electric motor; 12 - Inlet branch pipe of the inlet pipeline; 13 - CTS; 14 - Thermostat; 15 - Expansion tank; 16 - Expansion tank cover; 17 - Drain plug; 18 - Inlet pipe; 19 - Inlet pipe
On all models of cars of the brand in question, a closed-type cooling system operating under pressure is used. The system includes a water pump driven by a timing belt on 1.6L models and an auxiliary drive on others, a cross-flow aluminum radiator, an electric fan, a thermostat, a heater heat exchanger, as well as all connecting fittings and electrical switches.. Cold coolant from the radiator through the lower hose enters the water pump, which supplies it to the galleries of the block and cylinder head (as well as in the interior heater heat exchanger). After removing heat from the surfaces of the cylinders, combustion chambers and valve seats, the coolant reaches the bottom of the thermostat, which is initially closed. Next, the coolant passes through the heater heat exchanger, after which it returns back to the water pump.
The functional diagram of the engine cooling system is shown in the accompanying illustration. The cooling system functions as follows: a centrifugal water pump takes cold coolant from the bottom of the radiator through the lower radiator hose and pumps it under pressure through the galleries of the water jacket of the block and cylinder head, and, if equipped, also through the oil cooler heat exchanger. Having removed heat from the cylinders, combustion chambers and valve seats, the liquid enters the lower part of the thermostat, the valve of which remains closed during the engine warm-up stage and then opens. In addition to cooling the engine, the coolant is also used to heat the car interior. For this purpose, a heater heat exchanger is included in the cooling system path, passing through which the liquid returns back to the cylinder block.
Until the engine has warmed up to a certain temperature, the coolant continues to circulate in a short circuit, passing only through the block and cylinder head, as well as through the heater heat exchanger. As soon as the engine temperature reaches the set value, the thermostat opens, as a result of which a radiator is connected to the fluid circulation circuit. In the radiator, convective heat transfer from the liquid to the oncoming air flow occurs, the efficiency of which is determined by the developed area of the radiator heat exchanger fins and the speed of the air flow around them. If necessary, additional cooling of the radiator is provided by turning on the electric fan of the cooling system. When the liquid reaches the lower cavity of the radiator, the cycle repeats.
An electric fan controlled by a temperature-sensitive cooling system switch is installed behind the radiator. As soon as the temperature of the coolant reaches a certain set value, the fan turns on, as a result of which the airflow to the radiator heat exchanger increases, which leads to an increase in the efficiency of heat transfer.
Precautionary measures
Attention! To avoid scalding, never remove the expansion tank cap or disconnect any components of the cooling path when the engine is hot. If it becomes necessary to remove the reservoir cap before the coolant has completely cooled (such situations should be avoided whenever possible), you must first relieve excess pressure in the system. Wrap the tank cap with a thick layer of rags, then slowly unscrew until a hiss appears. When the hissing noise indicating release of steam stops, slowly unscrew the lid all the way. If the hissing does not resume at the last stage of unscrewing, the cap can be removed. During the entire procedure, do not tilt your face over the neck of the tank; wear rubber gloves to protect your hands.
Try to avoid getting antifreeze on exposed skin and paintwork on body panels. Accidental splashes should be washed off immediately with plenty of clean water. Never leave drained or fresh engine coolant stored in an open container. Collect traces of the strait immediately with rags. Remember that the sweet smell of antifreeze can attract the attention of children and animals. The ingress of even a small amount of coolant into the digestive tract of a living organism is fraught with the most serious consequences, even death.
Remember that when the engine is hot, the cooling fan continues to function even after the ignition is turned off - take care of your hands, try not to let hair or the edges of clothing come into contact with the impeller blades.
Precautions for models equipped with an air conditioning system are listed in Section Air conditioning system - general information and precautions.