The principle of operation of the cooling system. The cooling system of the engine: how is it and it is necessary to wash it in winter? Signs that it's time to rinse

(DVS) and their components are exposed to strong heating during the operation of various vehicles. At the same time, both overheating and the supercooling of the motor can provoke a failure of it. In this regard, one of the most important tasks of developers of power units is to ensure optimal thermal regime their work. A competently organized engine cooling system helps to obtain the best operational parameters of the DVS, to which:

1. Maximum power.
2. Minimum fuel consumption.
3. Increased service life.

The effect of temperature parameters for motor operation

In one working cycle temperature in cylinders of the DVS Changes from 80 ... 120 degrees Celsius during the inlet of a combustible mixture to 2000 ... 2200 degrees Celsius during its combustion. In this case, the power unit is strongly heated.

If the motor during operation is not cooled intensively, its parts are heated strongly and change in size. Significantly decreases (due to burnout) and the volume of engine oil, pumped into the crankcase. As a result, friction increases between interacting details, which leads to their rapid wear or even the encoding.

However, the intercooling of the DVS has a negative effect on its work. On the walls of the cold engine cylinders, the fuel vapor condensation occurs, which, washing the lubricant layer, drench motor oilIn Carter.

To eliminate the negative consequences associated with the heat violation, the cooling systems are designed to eliminate overheating and the supercooling of the motor during operation.

As a result, the chemical properties of the latter deteriorate, which contributes:

• increased consumption of engine oil;
• intensive wear of rubbing surfaces;
• falling power power aggregate;
• increase fuel consumption.

Classification

When the motor is running, it is necessary to ensure a removal of 25 to 35% of the heat released. For its effective absorption (removal) most often use water, air or special fluid (Tosol, antifreeze). The material of the coolant determines the method of cooling the power unit.

Distinguish systems:

1. Forced air cooling.
2. Liquid cooling with a closed cycle.

Liquid cooling system

Currently for effective cooling Automotive engines use a closed liquid cooling system with a closed cycle.

Design

In mandatory, the system contains an expansion tank, which serves to compensate for the change in the volume of the fluid when it changes its temperature. In addition, the coolant is poured through it.

Also, the system includes:

• water shirt of the power unit (the space between the double walls of the cylinder block and its heads in the discharge places of excessive amount of heat);
• temperature sensor;
• bimetallic or electronic thermostat providing optimum temperature in the system;
• pump-pump centrifugal type, providing forced circulation of coolant in the system;
• the fan with which the flow of opposite air is enhanced by the main radiator system;
• radiator transmission of heat environment;
• the heater radiator intended for heat transfer directly to the car's salon;
• control device built into the car instrument panel.

Operating principle

The coolant is poured into the system through the expansion tank. Constantly circulating inside the system, it takes heat from component parts The motor heating during operation is heated, falls into the radiator, cooled in the radiator by the oncoming air flow and returns back.

If necessary, fan turns on, enhancing cooling efficiency. For closed cooling systems, the temperature of the coolant should not exceed 126 degrees Celsius. Thus, the optimal thermal mode of operation of the power unit is ensured.

Additional functions

In addition to its main task - heat removal from heating elements, the liquid engine cooling system also provides:

• Warming up the power unit during the cold season

IN modern systems Liquid cooling is provided by two contours for which the coolant can circulate. This is done in order to at the time of starting the cold engine when its parts and the fluid itself have a low temperature, the coolant circulation was carried out in a small circle (by the radiator).

This is ensured by the thermostat, which at the moment when the temperature rises to a certain level (70-80 degrees Celsius), opens, giving the heat carrier to circulate big circle (Through the radiator). Thus, an accelerated engine warming up the engine.

• Air heating in the car

In the cold season, with the help of a hot heat carrier, air heats up in the car's cabin. To do this, serves an additional radiator installed in the cabin and equipped with its own fan. With their help, the heat selected from the hot liquid is distributed throughout the volume of the cabin.

• Reducing the temperature of the air injected into the air cylinders

Especially for engines equipped with turbocharger, two-circuit systems are provided, in which one circuit provides cooling of the liquid, and the second is cooling the air.

In addition, the coolant cooling circuit is also a two-circuit system, one circuit of which cools the head of the cylinder block, and the other is the block itself.

This is caused by the fact that turbocharged motor The temperature of the cylinder head should be below the temperature of the block itself at 15 ... 20 degrees Celsius. A feature of such a cooling system is that each contour is controlled by its own thermostat.

Advantages and disadvantages

The liquid engine cooling system is practically at all modern cars. A fundamentally different from air cooling systems, it guarantees:

• uniform and rapid warming of the power unit;
• effective heat removal in all operating conditions of the engine;
• reduction of power costs;
• stable thermal mode of operation of the motor;
• the possibility of using heat released to heat the air in the cabin, etc.

Among the few flaws of the liquid cooling system can be noted:

• the need for regular maintenance and complexity of repair;
• increased sensitivity to temperature changes.

Malfunctions and ways to eliminate them

All liquid cooling systems are characteristic characteristic malfunctions. Most often found:

1. the encoding of the thermostat in the closed position (the circulation of the fluid is carried out in a small circle);
2. pump breakage;
3. damage exhaust valvebuilt into a plug expansion tank;
4. the leakage of the coolant due to the depressurization of the system (damage to the seals, corrosion, etc.).
5. In addition, quite often the thermostat jars in the "open" position (coolant circulates by a large circle), which increases the heating time of the cold motor and contributes to the instability of the thermal regime during its further operation.

All of these faults are characterized by a significant increase in the operating temperature of the power unit, which can lead to the boiling of the coolant and overheating the motor.

All defects are eliminated by replacing faulty and / or damaged parts or components.

Air cooling system

Air cooling motors were equipped with vehicles in the 50-70 years of the last century. Typical representatives of such cars are "Zaporozhets" or Fiat 500. Now air-cooled motors in the automotive industry are practically not found.

Construction and principle of operation

Constructively, the forced air cooling system is mounted in the subcontrol space vehicle And consists of:

• suction or injection fan;
• guide ribs engine cooling shirts;
• controls ( throttle valves, air control or coupling controlling the fan speed automatically);
• temperature sensor installed in the power unit;
• control device derived dashboard In the car.

Cooling the motor is carried out by opposite cold air. To enhance its stream, the injection type fan is most often used. It enhances the flow of cold dense air and provides its feed in large quantities at low energy costs.

The suction fan requires high power costs, but provides a more uniform heat removal from the parts of the power unit.

Advantages and disadvantages

Motors with forced air cooled differ:

• ease of design;
• low requirements for changing the ambient temperature;
• slight weight;
• uncomplicated maintenance.

The disadvantages of the air cooling system include:

• greater loss of motor power, which is spent on ensuring fan operation;
• high noise during fan operation;
• insufficient cooling of individual engine elements due to uneven blowing;
• the impossibility of using excess heat to heating the cabin.

The cooling system is designed to remove heat from the mechanisms and parts of the engine, as well as to maintain the normal thermal mode of the engine.

Liquid systems with automotive engines received the most distribution with forced circulation Coolant.

Such systems are more efficient in operation and together with starting devices provide easy engine start at negative ambient air temperatures and create less noise when it works (Fig. 1).

The cooling system consists of:

shirts cooling the block and head of the cylinder block;

centrifugal pump;

thermostat 4;

radiator with expansion tank 1;

fan 3;

connecting nozzles and hoses.

The cooling system is filled with liquid through the expansion tank 6 (Fig. 3) or the neck of the radiator.

In the radiator lid or the tank, a steam valve is made, which supports increased pressure in the cooling system during engine operation, thereby increasing the temperature of the toosol.

Fig.1.

1 - radiator; 14 - piston; 2 - lid; 15 - drain crane; 3 - fan; 16 - lower radiator tank; 4 - thermostat; 5 - liquid pump; 6 - expansion tank; 7 - cylinder head; 8 - pipeline to heater; 9 - fluid temperature pointer; 10 - heater fan; 11 - heater radiator; 12 - shirt Cooling Cylinder Head; 13 - Shirt Cooling Cylinder Block.

As the engine is cool, the valve gradually reduces the pressure, preventing the radiator and the expansion tank. To drain the liquid, the holes are opened at the bottom of the radiator and the cylinder block, closed with threaded plugs or taps15.

During the engine operation, the liquid circulates in the engine cooling system under the action of a centrifugal liquid pump of 15 coolant liquid. The fluid flow distribution controls the thermostat.

While the engine does not warm, the liquid circulates in a small circle. In fact, within the shirt cooling the head and block of cylinders. As the engine is heated, the thermostat valve opens, and part of the fluid, and then its entire flow is directed to the radiator (large circulation circulation), where it is cooled by the flux of the incident air and the fan.

The impeller of the fan on some engines is driven by the belt transmission from pulley crankshaft. A more modern design is an electric cooling system fan, which runs from the cargo power grid and controlled by a thermal sensor installed in the radiator tank.

The engine cooling system is constructively combined with the car heating system of the car's passenger compartment. The heated liquid enters the heater radiator8 from the cylinder head cooling shirt on the upper pipeline, and the coolant pump is discharged along the lower pipeline.

The fluid flow through the heater radiator is adjustable or overlaps with a heater with a heater, managed from the driver's seat.

In addition to main function Wire heat from the main engine nodes of the car, the cooling system solves a number of additional tasks. In fact, it participates in the work, heating of the salon, exhaust and recycling of exhaust gases, turbocharging and gearboxes. About how it is arranged, as well as what is the principle of operation of the cooling system and will be discussed below.

Types of engine cooling systems

Temperature control car Engine It can be carried out using a coolant (antifreeze, coolant) and by circulating air. Based on this, three types of systems differ:

• Aerial. Physically consistently blowing, due to which hot air is displaced from open space in atmosphere. Air cooling may be natural and forced (using the fan). Due to low efficiency, as an independent system is practically not applied.
• Liquid. It is a system of tubular contours through which the coolant circulates. Liquid cooling may be forced (pumping the pump), the thermophone (due to the difference in the density of heated and cooled liquids) and combined (cooling the head of the cylinder block is forcibly carried out, and the remaining nodes in the thermophone principle). Such a system is more effective in comparison with air, but with certain modes of operation (long-term simple with the engine turned on, elevated ambient temperatures) may be insufficient for high-quality cooling.
• Combined. It is the use and air blowing, and liquid contours.

Liquid-based cooling systems are also divided into open and closed. The first have a message with an atmosphere with a steam tube, and in the second liquid is completely isolated from the environment. In closed systems, the pressure of antifreeze is greater, and therefore above and the boiling point. This allows them to be used at high heating temperatures of the fluid (up to 120 ° C).

Device and principle of operation of the cooling system

Engine cooling system

The most popular in modern cars is a combined engine cooling system with forced circulation of air and liquid. It consists of the following elements:

• Radiator cooling system.
• Small and large cooling contours.
• Cooling System Shirt (Channel System in Cylinder Block).
• Temperature sensor.
• Thermostat.
• Expansion tank.
• Pump (pump).
• Radiator stove.
• Oil radiator (optional).
• Radiator (optional).

At the time of launching the engine, the pump begins to pump the liquid over a small contour. When the engine is heated to the operating temperature, it works and opens the second (large) cooling circuit. Passing through the motor nodes, the coolant is heated and expands. With increasing temperature, part of the fluid enters the expansion tank. This allows you to compensate for the excess volume, regardless of how the pressure is established in the system.

Large and small circles circulation

Passing through the radiator section of the cooling system, the antifreeze cools again and returns to a new cycle. If this temperature reduction mode is insufficient, the temperature sensor is triggered transmitting the motor control unit and the air-cooled fan. If it is not enough, an engine overheating signal is not enough to the dashboard (indicator).

The oil radiator and the recycling radiator of the exhaust gases may not be present in all cooling systems. They are needed to simultaneously reduce the temperature of lubrication and exhaust, which makes the operation of the car more secure and economical. In cars, another cooling circuit may be present to reduce the air temperature.

How the engine cooling radiator is arranged

System radiator device cooling in DVS

The radiator of the cooling system system consists of the following items:

• Core. It can be tubular (vertical tubes of oval or circular cross section, combined with thin horizontal plates), lamellar (curved pairs of plates, soldered along the edges) and cellular (soldered tubes with a cross section in the form of a regular hexagon).
• Top tank. Equipped with a filling neck with a hermetic plug, as well as a nozzle for installing the hose supplying antifreeze. In the neck, a hole is made to install a warehouse tube. The latter has a steam valve that opens in case of boiling.
• Air valve. It is necessary for filling the radiator by air after stopping the engine. When the coolant is completely cooled, without supplying an additional air volume in the system there may be a strong vacuum, provoking squeezing tubes.
• Lower tank. Equipped with a nozzle for fastening the fluid removal hose.
• Fastening.

The principle of the operation of the radiator is based on multi-level air circulation in its core, which makes a decrease in the temperature of the coolant passing through it, more intense.

The most effective is the radiators of a plate type, but they are subject to rapid pollution, and therefore the most popular structural designs are tubular.

Features of the operating temperature sensor

Cooling system temperature sensor

The temperature sensor allows you to monitor the system status. Determine where the coolant temperature sensor is simply: as a rule, it is located in the Cylinder Head Channel. It is a thermistor in a hermetic case, which can be made of bronze, plastic and brass. The case has a carving for installation in the channel.

The principle of operation of the sensor is based on the following effect: with increasing temperature, the resistance of the sensing element is reduced, and with decrease it increases. Resistance indicator is transmitted to the electronic unit Engine control. So at the same time, these coolant states were accurate, the sensor must be completely immersed in it. At a temperature of 100 ° C, the resistance of the coolant temperature sensor must be about 177 ohms. Taking into account the measurement errors, the resistance indicator is allowed 190 ohms. If deviations are more permissible, the sensor must be replaced.

In some models, there may be two temperature sensors. One is responsible solely for the inclusion of the radiator fan, and the second is the sensor of the current coolant temperature pointer.

What is used as cooling liquids

Expansion Tank Cooling System

In the role working fluid In cooling systems, distilled or deionized water was originally used. However for modern engines It does not provide the desired range of operating temperatures. In addition, it is prone to corrosion activity against metals, which reduces the service life of the cooling system. To eliminate these shortcomings, compounds with special additives (ethylene glycol, corrosion inhibitors) are used as coolant today, which increases the characteristics of the entire system. Most often used antifreeze, which has a lower freezing threshold.

If the situation occurs when an emergency coolant topping is required, you can use the usual clean water. However, for the correct operation of the system, at the first opportunity, such a solution must be replaced with high-quality antifreeze.

Replacing the coolant is carried out every 60-100 thousand mileage kilometers. In the cooled state (when the engine is turned off), its number must be at the level of the lower edge of the coolant expansion tank nozzle. For convenience, MIN and MAX marks are made on it. When the amount of fluid below the minimum mark - perform the topping. If after work the level fell again - this indicates the depressurization of the system.

The significance of the engine cooling system does not cause doubt. Therefore, it is worth regularly conducting a prophylactic inspection of its main nodes. This will avoid engine overheating and the occurrence of critical breakdowns.

Cooling system - This is a set of devices that provide forced heat removal from the heating engine parts.

The need for cooling systems for modern engines is caused by the fact that the natural dispersion of heat by outer surfaces of the engine and the heat sink into the circulating engine oil does not provide the optimal temperature mode of the engine and some systems. Overheating of the engine is associated with a deterioration in the process of filling the cylinders with fresh charge, the burning of the oil, an increase in friction losses and even the piston jam. On the gasoline engines There is also a danger of a vibil ignition (not from the spark of the candle, but due to the high temperature of the combustion chamber).

The cooling system should ensure the automatic maintenance of the optimal thermal mode of the engine on all speed and load modes of its operation at ambient air temperature -45 ... + 45 ° C, fast warming engine to operating temperature, minimum power consumption for actuating system units, low weight and small dimensions, operational reliability, determined by service life, simplicity and convenience of maintenance and repair.

On modern wheeled and tracked machines, air and liquid cooling systems are used.

When using the cooling air system (Fig. A), heat from the head and the cylinder block is transmitted directly by airing their air. Through the air shirt, the image of the casing 3, the cooling air is driven by a fan 2 driven by the crankshaft using the belt transmission. To improve the heat sink of cylinders 5 and their heads are equipped with ribs 4. The cooling intensity is regulated by special air dampers 6, controlled automatically using air thermostats.

Most modern engines have a liquid cooling system (Fig. B). The system includes cooling shirts 11 and 13, respectively, heads and blocks of cylinders, radiator 18, upper 8 and lower 16 coupling pipes with hoses 7 and 15, liquid pump 14, distribution pipe 72, thermostat 9, expansion (compensatory) tank 10 and fan 77 . In the cooling shirt, radiator and nozzles there is a coolant (water or antifreeze - non-freezing liquid).

Fig. Air (s) and liquid (b) engine cooling systems:
1 - belt transmission; 2, 17 - fans; 3 - casing; 4 - cylinder ribs; 5 - cylinder; 6 - air damper; 7, 15 - hoses; 8, 16 - upper and lower connecting nozzles; 9 - thermostat; 10 - expansion tank; 77, - shirts of cooling head and cylinder block; 12 - distribution pipe; 14 - Liquid pump; 18 - radiator

When the engine is running, the liquid pump acts on the crankshaft shaft creates a cooling fluid circulation in the system. In the distribution pipe 12, the liquid is sent first to the most heated parts (cylinders, block head), cools them and on the nozzle 8 enters the radiator 18. In the radiator, the fluid flow branches himself along the tubes on thin jets and is cooled by air, blowing through the radiator. The cooled liquid from the lower tank of the radiator on the nozzle 16 and the hose 15 enters the liquid pump again. The air flow through the radiator usually creates a fan 77, driven by a crankshaft or a special electric motor. On some tracked machines, an ejection device is used for ensuring air flow. The principle of operation of this device is to use the exhaust gas energy flowing at high speed from the exhaust pipe and fond of air.

Regulates the circulation of fluid in the radiator, maintaining the optimum temperature of the engine, thermostat 9. The higher the temperature of the fluid in the shirt, the more significant the thermostat valve is open and more fluid enters the radiator. At low engine temperature (for example, immediately after it start), the thermostat valve is closed, and the liquid is sent to the radiator (by a large circulation of circulation), and immediately in the pump receiving cavity (for a small circle). This achieves a quick engine warming after starting. The cooling intensity is also adjustable using the blinds installed at the inlet of the air tract or output from it. The greater the degree of closure of the blinds, the less air passes through the radiator and worse cooling of the liquid.

In the expansion tank 10, located above the radiator, there is a supply of fluid to compensate for its decrease in the circuit due to evaporation and leaks. In the upper cavity of the expansion tank, the resulting pair from the top collector of the radiator and the cooling shirts is often discharged.

Liquid cooling compared to air has the following advantages: Easy engine starting in conditions of low ambient air temperature, more uniform engine cooling, the possibility of applying block structures of cylinders, simplification of layouts and the possibility

air tract isolation, smaller engine noise and lower mechanical stresses in its details. At the same time, the liquid cooling system has a number of disadvantages, such as a more complex design of the engine and system, the need for coolant and more frequent oil change, the danger of leakage and freezing of fluid, increased corrosion wear, considerable fuel consumption, more complex maintenance and repair. , as well as (in some cases) increased sensitivity to the change in ambient temperature.

Liquid pump 14 (see Fig. B) Provides the cooling fluid circulation in the system. Centrifugal impeller pumps are usually used, but sometimes gear and piston pumps are used. Thermostat 9 may be single and two-flaped with a liquid thermosular element or an element containing a solid filler (Cersein). In any case, the material for the thermosyl element must have a very large volumetric extension coefficient so that the thermostat valve rod can move on a rather long distance when heated.

Practically, all terrestrial vehicle engines with liquid cooling are equipped with so-called closed cooling systems that do not have a permanent connection with the atmosphere. In this case, an overpressure is formed in the system, which leads to an increase in the boiling point of the liquid (up to 105 ... 110 ° C), an increase in the cooling efficiency and reduce losses, as well as a reduction in the probability of air and steam bubbles in the flow of liquid.

Maintaining the necessary overpressure in the system and ensuring access to it atmospheric air at a permit is carried out using a double steam truck valve, which is installed in the highest point of the liquid system (usually in the lid of the bulk neck of the expansion tank or radiator). The steam valve opens, allowing the excess of the pair to go into the atmosphere if the pressure in the system exceeds atmospheric to 20 ... 60 kPa. The air valve opens when the pressure in the system is reduced by 1 ... 4 kPa compared to atmospheric (after stopping the engine coolant cools, and its volume decreases). The pressure drops in which the valves are open are provided by the selection of valve springs.

In the liquid ventilation system of cooling, the radiator is washed by the air flow created by the fan. Depending on the relative positions of the radiator and the fan, the following types of fans can be applied: axial, centrifugal and combined, creating both axial and radial air flows. Axial fans are installed in front of the radiator or behind it in a special air-powered channel. The air is supplied to the centrifugal fan along the axis of its rotation, and is given to the radius (or vice versa). When the radiator is located in front of the fan (in the suction area), the air flow in the radiator is more uniform, and the air temperature is not raised due to its mixing with a fan. When the radiator is found behind the fan (in the injection area), the air flow in the turbulent radiator, which increases the cooling intensity.

On heavy wheeled and caterpillar vehicles, the fan actuator is usually carried out from the crankshaft of the engine. Cardanium, belt and gear (cylindrical and conical) transmissions can be used. In order to reduce dynamic loads on the fan in its crankshaft drive, unloading and damping devices are often used in the form of torsion rollers, rubber, friction and viscous couplings, as well as hydromeuft. To drive the fan relatively low-power engines Special electric motors are widely used, the power is carried out from the onboard electrical system. This, as a rule, reduces the mass power plant And simplifies its layout. In addition, the use of an electric motor for the actuator drive allows you to adjust the frequency of its rotation, and therefore the intensity of the cooling. With low cooling fluid temperature, automatic shutdown of the fan is possible.

Radiators bind with each other air and liquid paths of the cooling system. Purpose of radiators - transmission of heat from coolant atmospheric air. The main parts of the radiator are input and output collectors, as well as the core (cooling grille). The core is made of copper, brass or aluminum alloys. By type of core distinguish the following types of radiators: tubular, tubular-plate, tubular-tape, plate and cellular.

In the cooling systems of the wheeled and tracked machines, tubular-plate and tubular-tape radiators were obtained the greatest distribution. They are tough, durable, technologically in production and have high thermal efficiency. Tubes of such radiators have, as a rule, a plane cross section. Tubular-plate radiators can also consist of round or oval tubes. Sometimes the tube of the plane-mounted section is located at an angle of 10 ... 15 ° to the airflow, which contributes to the turbulization (twist) of air and increases the heat transfer of the radiator. Plates (ribbons) can be smooth or corrugated, with pyramidal protrusions or bent spacing. Corrugating the plates, applying spacing and protrusions increase the cooling surface and provide turbulent air flow between tubes.

Fig. Lattices of tubular plate (a) and tubular-belt (b) radiators

Engine cooling system internal combustion Designed to remove unnecessary heat from parts and engine nodes. In fact, this system is harmful to your pocket. Approximately one third of the warmth obtained from the combustion of precious fuel is necessary to disperse in the environment. But such is the device of modern engine. Ideal would be a motor that can work without removal of warmth in environment, And all it turns it into useful work. But the materials used in modern engine building, such temperatures will not stand. Therefore, at least two main, basic parts of the engine - the cylinder block and the block head - it has to be additionally cooled. At the dawn of the automotive industry, two cooling systems were competed for a long time: liquid and air. But aerial system Cooling gradually handed over its position and is now used, mainly on very small motor transport engines and generator installations low power. Therefore, we consider in more detail the liquid cooling system.

Cooling system device

The cooling system of a modern automotive engine includes a motor cooling shirt, a coolant pump, a thermostat, connecting hoses and a radiator with a fan. The heat exchanger of the heater is connected to the cooling system. In some engines, the coolant is also used for heating the throttle node. Also, engines with the supervision system occurs in the flow of coolant into liquid-air intercoolers or the turbocharger itself to reduce its temperature.

The cooling system is quite simple. After starting the cold engine, the coolant begins with a pump to circulate for a small circle. It passes through the cooling shirt of the block and the engine cylinders head and returns to the pump through the bypass (bypass) nozzles. In parallel (on the overwhelming majority of modern cars), the liquid is constantly circulating through the heater heat exchanger. As soon as the temperature reaches a given value, usually about 80-90 ° C, the thermostat begins to open. Its primary valve directs the flow into the radiator, where the liquid is cooled by the oncoming air flow. If the air blowing is not enough, the cooling system fan is enhanced, in most cases having an electric drive. The fluid movement in all other nodes of the cooling system continues. Often the exception is the bypass channel, but it is not closed on all cars.

The schemes of cooling systems in recent years have become very similar to one another. But there are two fundamental differences. The first is the location of the thermostat before and after the radiator (along the movement of the fluid). The second difference is the use of a circulating expansion tank under pressure, or a tank without a pressure, which is a simple backup volume.

On the example of three cooling system schemes, we will show the difference between these options.

Components

Shirt head and cylinder block There are channels cast in an aluminum or cast iron product. Channels are sealed, and the joint and cylinder heads are sealed with a gasket.

Cooling fluid pump paddle, centrifugal type. Is driven either timing beltor a belt drive auxiliary units.

Thermostatit is an automatic valve that is triggered when a certain temperature is reached. It opens, and part of the hot liquid is reset into the radiator, where it cools. Recently, the electronic control of this simple device has been applied. Coolant has begun to warm up a special tenan for an earlier discovery of the thermostat in case of need.

Replacing fluid and flushing

If I did not have to replace any node in the cooling system earlier, the instructions recommend changing antifreeze at least 5-10 years. If you did not have to add water from the canister into the system, and even worse - from the roadside dials, then when replacing the liquid, the system can not be flushed.

But if the car has seen a lot in its century, then when replacing the liquid it is useful to produce. Outping in several places the system can be ringed with a jet of water from the hose carefully. Either just drain the old liquid and pour clean, boiled water. Run the engine and warm up to operating temperature. After the system cools down, so as not to burn, drain the water. Then blow the system and fill the fresh antifreeze.

Washing the cooling system is usually covered in two cases: when the engine overheats it (it is primarily in the summer) and when it ceases to warm the stove in the winter. In the first case, the cause lies in the dirt outside and clogged from the inside tubes of the radiator. In the second, the problem is that they have been hammered by the deposits of the heater radiator tube. Therefore, with a planned change of fluid and when replacing the cooling system components, do not miss the capabilities to rinse all nodes.