The device and self-diagnosis of malfunctions of the cooling system VAZ 2107
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The device and self-diagnosis of malfunctions of the cooling system VAZ 2107

The operation of the internal combustion engine of any car is associated with high temperatures. The internal combustion engine heats up during the combustion of the fuel-air mixture in the cylinders and as a result of the friction of its elements. The cooling system helps to avoid overheating of the power unit.

General characteristics of the cooling system VAZ 2107

The VAZ 2107 engine of all models has a sealed liquid cooling system with forced circulation of the coolant (coolant).

Purpose of the cooling system

The cooling system is designed to maintain the optimum temperature of the power unit during its operation and timely controlled removal of excess heat from the heating units. Individual elements of the system are used to heat the interior during the cold season.

Cooling parameters

The VAZ 2107 cooling system has a number of parameters that affect the operation and performance of the power unit, the main of which are:

  • the amount of coolant - regardless of the method of fuel supply (carburetor or injection) and engine size, all VAZ 2107 use the same cooling system. According to the manufacturer's requirements, 9,85 liters of refrigerant is required for its operation (including interior heating). Therefore, when replacing antifreeze, you should immediately purchase a ten-liter container;
  • engine operating temperature - The operating temperature of the engine depends on its type and volume, the type of fuel used, the number of revolutions of the crankshaft, etc. For the VAZ 2107, it is usually 80–950C. Depending on the ambient temperature, the engine warms up to operating condition within 4-7 minutes. In case of deviation from these values, it is recommended to immediately diagnose the cooling system;
  • coolant working pressure - Since the VAZ 2107 cooling system is sealed, and the antifreeze expands when heated, a pressure exceeding atmospheric pressure is created inside the system. This is necessary to increase the boiling point of the coolant. So, if under normal conditions water boils at 1000C, then with an increase in pressure to 2 atm, the boiling point rises to 1200C. In the VAZ 2107 engine, the operating pressure is 1,2–1,5 atm. Thus, if the boiling point of modern coolants at atmospheric pressure is 120–1300C, then under working conditions it will increase to 140–1450C.

The device of the cooling system VAZ 2107

The main components of the VAZ 2107 cooling system include:

  • water pump (pump);
  • main radiator;
  • main radiator fan;
  • heater (stove) radiator;
  • stove tap;
  • thermostat (thermoregulator);
  • expansion tank;
  • coolant temperature sensor;
  • coolant temperature sensor pointer;
  • control temperature sensor (only in injection engines);
  • fan switch on sensor (only in carburetor engines);
  • connecting pipes.

Read about the thermostat device: https://bumper.guru/klassicheskie-modeli-vaz/sistema-ohdazhdeniya/termostat-vaz-2107.html

This should also include the engine cooling jacket - a system of special channels in the cylinder block and block head through which the coolant circulates.

The device and self-diagnosis of malfunctions of the cooling system VAZ 2107
The VAZ 2107 cooling system is arranged quite simply and consists of a number of mechanical and electrical components

Video: device and operation of the engine cooling system

Water pump (pump)

The pump is designed to ensure continuous forced circulation of coolant through the engine cooling jacket during engine operation. It is a conventional centrifugal-type pump that pumps antifreeze into the cooling system using an impeller. The pump is located on the front of the cylinder block and is driven by the crankshaft pulley through a V-belt.

Pump design

The pump consists of:

How the pump works

The principle of operation of a water pump is quite simple. When the crankshaft rotates, the belt drives the pump pulley, transferring torque to the impeller. The latter, rotating, creates a certain coolant pressure inside the housing, forcing it to circulate inside the system. The bearing is designed for uniform rotation of the shaft and reduces friction, and the stuffing box ensures the tightness of the device.

Pump malfunctions

The pump resource regulated by the manufacturer for the VAZ 2107 is 50–60 thousand kilometers. However, this resource may decrease in the following situations:

The result of the influence of these factors are:

If such malfunctions are detected, the pump should be replaced.

Main radiator

The radiator is designed to cool the coolant entering it due to heat exchange with the environment. This is achieved due to the peculiarities of its design. The radiator is installed in the front of the engine compartment on two rubber pads and is attached to the body with two studs with nuts.

Radiator design

The radiator consists of two vertically located tanks and tubes connecting them. On the tubes there are thin plates (lamellas) accelerating the heat transfer process. One of the tanks is equipped with a filler neck that closes with an airtight stopper. The neck has a valve and is connected to the expansion tank with a thin rubber hose. In carburetor VAZ 2107 engines, a landing slot is provided in the radiator for the sensor for turning on the cooling system fan. Models with injection engines do not have such a socket.

The principle of the radiator

Cooling can be carried out both naturally and forcibly. In the first case, the temperature of the refrigerant is reduced by blowing the radiator with an oncoming air flow while driving. In the second case, the air flow is created by a fan attached directly to the radiator.

Radiator malfunctions

The failure of the radiator is most often associated with loss of tightness as a result of mechanical damage or corrosion of the tubes. In addition, the pipes can become clogged with dirt, deposits and impurities in the antifreeze, and the coolant circulation will be disturbed.

If a leak is detected, the damage site can be tried to be soldered with a powerful soldering iron using a special flux and solder. Clogged tubes can be eliminated by flushing with chemically active substances. Orthophosphoric or citric acid solutions, as well as some household sewer cleaners, are used as such substances.

Cooling fan

The fan is designed for forced airflow to the radiator. It turns on automatically when the coolant temperature rises to a certain value. In VAZ 2107 carburetor engines, a special sensor installed in the main radiator is responsible for turning on the fan. In injection power units, its operation is controlled by an electronic controller, based on the readings of the temperature sensor. The fan is fixed on the main radiator body with a special bracket.

Fan design

The fan is a conventional DC motor with a plastic impeller mounted on the rotor. It is the impeller that creates the air flow and directs it to the radiator lamellas.

The voltage for the fan is supplied from the generator through a relay and a fuse.

Fan malfunctions

The main malfunctions of the fan include:

To check the performance of the fan is connected directly to the battery.

Radiator and faucet stoves

The stove radiator is designed to heat the air entering the cabin. In addition to it, the interior heating system includes a stove fan and dampers that regulate the direction and intensity of the air flow.

Construction of radiator stoves

The stove radiator has the same design as the main heat exchanger. It consists of two tanks and connecting pipes through which the coolant moves. To accelerate heat transfer, the tubes have thin lamellas.

To stop the supply of warm air to the passenger compartment in summer, the stove radiator is equipped with a special valve that shuts off the coolant circulation in the heating system. The crane is put in action by means of a cable and the lever located on the forward panel.

The principle of operation of the stove radiator

When the stove tap is open, hot coolant enters the radiator and heats the tubes with lamellas. The air flows passing through the stove radiator also heat up and enter the passenger compartment through the air duct system. When the valve is closed, no coolant enters the radiator.

Malfunctions of the radiator and stove tap

The most common breakdowns of the radiator and stove tap are:

You can repair the stove radiator in the same ways as the main heat exchanger. If the valve fails, it is replaced with a new one.

Thermostat

The thermostat maintains the required thermal mode of operation of the engine and reduces its warm-up time at start-up. It is located to the left of the pump and is connected to it with a short pipe.

Thermostat design

The thermostat consists of:

The thermoelement is a sealed metal cylinder filled with special paraffin. Inside this cylinder there is a rod that actuates the main thermostat valve. The body of the device has three fittings, to which the inlet hose from the pump, bypass and outlet pipes are connected.

How the thermostat works

When the coolant temperature is below 800C The main thermostat valve is closed and the bypass valve is open. In this case, the coolant moves in a small circle around the main radiator. Antifreeze flows from the engine cooling jacket through the thermostat to the pump, and then enters the engine again. This is necessary so that the engine warms up faster.

When the coolant is heated to 80–820C main thermostat valve starts to open. When antifreeze is heated to 940C, this valve opens fully, while the bypass valve, on the contrary, closes. In this case, the coolant moves from the engine to the cooling radiator, then to the pump and back to the cooling jacket.

More about the device of the cooling radiator: https://bumper.guru/klassicheskie-modeli-vaz/sistema-ohdazhdeniya/radiator-vaz-2107.html

Thermostat malfunctions

If the thermostat fails, the engine can either overheat or heat up more slowly to operating temperature. This is the result of valve jamming. It's easy to check if the thermostat is working. To do this, you need to start a cold engine, let it run for two or three minutes and touch the pipe that goes from the thermostat to the radiator with your hand. It must be cold. If the pipe is warm, then the main valve is constantly in the open position, which, in turn, will lead to a slow warm-up of the engine. Conversely, when the main valve shuts off the flow of coolant to the radiator, the lower pipe will be hot and the upper one will be cold. As a result, the engine will overheat and the antifreeze will boil.

You can more accurately diagnose a thermostat malfunction by removing it from the engine and checking the behavior of the valves in hot water. To do this, it is placed in any heat-resistant dish filled with water and heated, measuring the temperature with a thermometer. If the main valve began to open at 80–820C, and fully opened at 940C, then the thermostat is OK. Otherwise, the thermostat has failed and needs to be replaced.

Expansion tank

Since antifreeze increases in volume when heated, the design of the VAZ 2107 cooling system provides for a special reservoir for accumulating excess coolant - an expansion tank (RB). It is located on the right side of the engine in the engine compartment and has a plastic translucent body.

Construction dad

RB is a plastic sealed container with a lid. To maintain the reservoir close to atmospheric pressure, a rubber valve is installed in the lid. At the bottom of the RB there is a fitting to which a hose is connected from the neck of the main radiator.

On one of the walls of the tank there is a special scale for assessing the level of coolant in the system.

Principle of action father

When the coolant heats up and expands, excess pressure is created in the radiator. When it rises by 0,5 atm, the neck valve opens and excess antifreeze begins to flow into the tank. There, the pressure is stabilized by a rubber valve in the lid.

Tank malfunctions

All RB malfunctions are associated with mechanical damage and subsequent depressurization or failure of the cover valve. In the first case, the entire tank is changed, and in the second, you can get by with replacing the cap.

Temperature sensor and fan on sensor

In carburetor models VAZ 2107, the cooling system includes a fluid temperature indicator sensor and a fan switch sensor. The first is installed in the cylinder block and is designed to control the temperature and transmit the information received to the dashboard. The fan switch sensor is located at the bottom of the radiator and is used to supply power to the fan motor when the antifreeze reaches a temperature of 920C.

The injection engine cooling system also has two sensors. The functions of the first are similar to the functions of the temperature sensor of carburetor power units. The second sensor transmits data to the electronic control unit, which controls the process of turning the radiator fan on and off.

Sensor malfunctions and methods for diagnosing them

Most often, the sensors of the cooling system stop working normally due to wiring problems or due to the failure of their working (sensitive) element. You can check them for serviceability with a multimeter.

The operation of the fan switch-on sensor is based on the properties of a bimetal. When heated, the thermoelement changes its shape and closes the electrical circuit. Cooling, it assumes its usual position and stops the supply of electric current. To check the sensor is placed in a container with water, after connecting the probes of the multimeter to its terminals, which is turned on in the tester mode. Next, the container is heated, controlling the temperature. At 920C, the circuit should close, which the device should report. When the temperature drops to 870C, a working sensor will have an open circuit.

The temperature sensor has a slightly different principle of operation, based on the dependence of resistance on the temperature of the medium in which the sensitive element is placed. Checking the sensor is to measure the resistance with changing temperature. A good sensor at different temperatures should have different resistance:

To check, the temperature sensor is placed in a container with water, which gradually heats up, and its resistance is measured with a multimeter in ohmmeter mode.

Antifreeze temperature gauge

The coolant temperature gauge is located on the lower left side of the instrument panel. It is a colored arc divided into three sectors: white, green and red. If the engine is cold, the arrow is in the white sector. When the engine warms up to operating temperature and then operates in normal mode, the arrow moves to the green sector. If the arrow enters the red sector, the engine is overheated. It is highly undesirable to continue moving in this case.

Connecting pipes

The pipes are used to connect the individual elements of the cooling system and are ordinary rubber hoses with reinforced walls. Four pipes are used to cool the engine:

In addition, the following connecting hoses are included in the cooling system:

Branch pipes and hoses are fastened with clamps (spiral or worm). To remove or install them, it is enough to loosen or tighten the clamp mechanism with a screwdriver or pliers.

Coolant

As a coolant for the VAZ 2107, the manufacturer recommends using only antifreeze. For an uninitiated motorist, antifreeze and antifreeze are one and the same. Antifreeze is usually called all coolants without exception, regardless of where and when they were released. Tosol is a kind of antifreeze produced in the USSR. The name is an abbreviation for "Separate Laboratory Organic Synthesis Technology". All coolants contain ethylene glycol and water. The differences are only in the type and amount of added anti-corrosion, anti-cavitation and anti-foam additives. Therefore, for the VAZ 2107, the name of the coolant does not matter much.

The danger is cheap low-quality coolants or outright fakes, which have recently become widespread and often found on sale. The result of the use of such liquids can be not only a radiator leak, but also the failure of the entire engine. Therefore, to cool the engine, you should buy coolants from proven and well-established manufacturers.

Learn how to change the coolant yourself: https://bumper.guru/klassicheskie-modeli-vaz/sistema-ohdazhdeniya/zamena-tosola-vaz-2107.html

Possibilities of tuning the cooling system VAZ 2107

There are various ways to increase the efficiency of the VAZ 2107 cooling system. Someone installs a fan from Kalina or Priora on the radiator, someone tries to heat the interior better by supplementing the system with an electric pump from the Gazelle, and someone puts silicone pipes, believing that with them the engine will warm up faster and cool down. However, the feasibility of such tuning is highly questionable. The VAZ 2107 cooling system itself is pretty well thought out. If all its elements are in good order, the engine will never overheat in summer, and in winter it will be warm in the cabin without turning on the stove fan. To do this, it is only necessary to periodically pay attention to the maintenance of the system, namely:

Thus, the VAZ 2107 cooling system is quite reliable and simple. Nevertheless, it also needs periodic maintenance, which even an inexperienced motorist can perform.

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