5.17.1. Features of a design

The engine cooling system liquid (with compulsory circulation of liquid), tight, with a broad tank.
The system is filled with the cooling liquid on the basis of ethylene glycol (antifreeze) which is not freezing at ambient temperature to –40 °C.

Fig. 5.16. Arrangement of elements of the cooling system: 1 – broad tank; 2 – heater hoses; 3 – thermostat; 4 – the sensor of the index of temperature of cooling liquid (on a photo it is not visible, located under the thermostat); 5 – sensor of temperature of cooling liquid; 6 – radiator hoses; 7 – stopper of a drain opening of a radiator; 8 – stopper of a drain opening of the block of cylinders; 9 – hoses of heating of throttle knot

The arrangement of elements of the cooling system is shown in fig. 5.16.

The replacement procedure of cooling liquid is described at the beginning of section 4 "Maintenance".

It is not recommended to fill the cooling system with water as the anticorrosive and anti-making foam additives, and also additives interfering adjournment of a scum are a part of antifreeze.
Cooling liquid is toxic! Avoid inhalation of its vapors and hit on skin.
In due time eliminate violation of tightness of the cooling system to avoid hit of vapors of cooling liquid in interior of the car at its operation. Your health is more expensive, than a new branch pipe of the cooling system or a tube of sealant!

Fig. 5.17. Cooling system: 1 – broad tank; 2 – stopper of a broad tank; 3 – the taking-away radiator hose; 4 – engine cooling system radiator; 5 – sensor of temperature of cooling liquid of a control system of the engine; 6 – the bringing radiator hose; 7 – thermostat; 8 – index sensor temperature of cooling liquid; 9 – laying of the thermostat; 10 – head of the block of cylinders; 11 – laying of the water pump; 12 – water pump; 13 – laying of the bringing pipe; 14 – the bringing pipe of the water pump; 15 – filling hose; 16 – a hose from the thermostat to the bringing tube of the water pump

The device of the cooling system is shown in fig. 5.17.
The water pump 12 (see fig. 5.17) centrifugal type provides compulsory circulation of liquid in the cooling system, is installed on the forward plane of the block of cylinders and is given to rotation by a gear belt of the drive of the camshaft. The closed bearings which are not needing lubricant replenishment are installed in the pump. The pump is not subject to repair, at refusal (a leak of liquid or damage of bearings) it is replaced assembled.
The thermostat 7 with a firm thermosensitive filler maintains the normal working temperature of cooling liquid and reduces time of warming up of the engine. It has the main and additional (perepuskny) valves. At a temperature of cooling liquid up to (85±2) °C the thermostat is completely closed and liquid circulates on a small contour, passing a radiator that accelerates warming up of the engine. At a temperature (85±2) °C the thermostat begins to open, and at 102 °C comes off completely, providing circulation of liquid through a radiator.
The electric fan 15 (fig. 5.18) with a plastic four-blade krylchatka provides a radiator purge with air at small speeds of the movement of the car generally in city conditions or on mountain roads when the counter flow of air is insufficient for cooling of a radiator.
For increase in overall performance the fan is installed in a casing 8 and attached to it in three points through rubber pillows. The casing, in turn, is attached to a radiator 4 in four points.
The control unit of the engine obtaining information on temperature of cooling liquid from the sensor 5 (see fig. 5.17) located in a thermostat 7 nest operates the electric fan.

Fig. 5.18. A radiator with the electric fan and a broad tank: 1 – broad tank; 2 – steam discharge hose of a radiator of a heater; 3 – steam discharge hose of a radiator of the cooling system; 4 – radiator; 5 – drain stopper; 6 – sealing ring of a drain stopper; 7 – radiator support pillow; 8 – electric fan casing; 9 – elastic plug; 10 – remote plug; 11 – washer; 12 – the washer is spring; 13 – nut; 14 – bolt; 15 – electric fan; 16 – stopper of a broad tank

Radiator 4 (see fig. 5.18) tubular and lamellar, aluminum, with plastic tanks, double-thread, with a partition in the left tank. In the lower part of the right tank there is a drain stopper 5. In tanks the bringing and taking away branch pipes of hoses to a water shirt of the engine and a branch pipe of the hose connecting a radiator to a broad tank are executed.
The broad tank 1 serves for compensation of the changing volume of cooling liquid depending on its temperature. The tank is made of translucent plastic. On its walls tags of "MAX" and "MIN" for control of level of cooling liquid are put, the bulk mouth which is hermetically closed by a plastic stopper 16 with two valves in it (inlet and final) assembled in the uniform block from above is located. The final valve opens with a pressure of 110 kPa (1,1 kgfs/cm2), providing temperature increase of the beginning of boiling of cooling liquid and preventing intensive steam formation. When cooling liquid its volume decreases and in system depression is created. The inlet valve in a stopper opens at depression about 3 kPa (0,03 kgfs/cm2) and passes air in a broad tank.

Serviceability of valves of a stopper is very important for normal operation of the cooling system, but often at emergence of problems (boiling of cooling liquid, etc.) motorists pay attention only to operation of the thermostat, forgetting to check valves. Leakage of the final valve leads to decrease in temperature of boiling of cooling liquid, and its jamming in the closed state — to emergency increase in pressure in system that can cause damage of a radiator and hoses.

The cooling system by means of hoses included a radiator of a heater of salon.
Possible malfunctions of the cooling system, their reason and ways of elimination are given in the table on.