The use of a liquid cooling system on cars allows you to maintain the temperature regime of the engine within certain limits in order to provide the most optimal conditions for the processes occurring inside the power plant.

But this system structurally complicates the design of the engine, in addition, it requires the presence of another engine working fluid - cooling. In this case, the liquid must circulate in order to remove heat from the most heated elements of the engine to ensure that the temperature is maintained within the specified limits. And since the cooling system is closed, the liquid must transfer the removed heat further, in the case of a car, to the environment, so that it can again take part of the heat. In fact, the liquid in the cooling system is just a "carrier" of heat, but it is more efficient than the air that cools the engine with an air-cooled system.

Why doesn't the water fit?

Initially, ordinary water was used as a liquid for cooling the power plant. She performed her functions quite effectively, but due to a number of negative qualities, she was practically abandoned.

The first and one of the most unfavorable factors of water as a cooling liquid is the negligible freezing threshold. Already at 0°C, water begins to crystallize. When the temperature drops, the water passes into a solid state - ice, while the transition is accompanied by an expansion of volume. As a result, frozen water in the cylinder block can break the cooling jacket, damage the pipelines and destroy the radiator tubes.

The second negative factor of water is its ability to deposit scale inside the cooling system, which reduces heat transfer, cooling efficiency drops. In addition, water can react with the metal, due to which a corrosion center may appear at the point of contact.

Cylinder Block Corrosion

Also, one of the significant negative qualities of water is the temperature threshold of boiling. The official boiling point of water is 100°C. But this indicator depends on many factors, one of which is the chemical composition.

Often the boiling point of water is below the set level, in some cases the boiling threshold can be 92-95°C. If we take into account that for many cars the engine temperature is considered to be optimal at the level of 87-92 ° C, then in such motors the water will work on the verge of boiling, and at the slightest excess of temperature it will turn into a gaseous state, with the termination of its main function - removal heat.

Because of these negative qualities, water was practically abandoned as a coolant. Although it is sometimes used in agricultural machinery engines, many rules must be observed.

Types of liquids for cooling

To replace water, they began to use special liquids - antifreezes, while the water did not go anywhere. Indeed, in fact, antifreeze is a mixture of water with materials that change its properties, first of all, lower the freezing point. Such materials can be inorganic salts (sodium and calcium chlorides), alcohols, glycerin, glycols, carbitols.

In internal combustion engines, aqueous solutions of glycols are most widely used. The composition and use of coolants for power plants of cars are almost identical, only special additives to them can differ.

Glycol-based antifreezes are optimal for use in vehicles.

An interesting fact is that a 40% solution of ethyl alcohol, that is, ordinary vodka, is considered the best antifreeze.

But alcohol vapors are flammable, so the use of such antifreeze on cars is unsafe.

As for the composition of glycol antifreezes, the main elements are water and glycol, and corrosion inhibitors, anti-cavitation and anti-foam additives, as well as dyes act as additives. Ethylene glycol is most commonly used, but propylene glycol-based coolant can also be found.

Positive properties of antifreeze

Let's go through the main positive qualities of glycol antifreeze:

• lower freezing point than water (this indicator depends on the percentage of glycols in the aqueous solution);
• glycol-based antifreezes have a significantly lower degree of expansion during freezing (Therefore, even at very low temperatures, when the solution crystallizes, the possibility of damage to engine elements is much lower than when using water);
• the boiling point of the glycol solution is over 110 ° C (also depends on the percentage of glycol and water);
• glycols in their composition have substances that provide lubrication of the elements of the system;

Antifreeze base

Ethylene glycol antifreezes are the most common because of the low cost of their production. Their main disadvantage is their high toxicity. They can cause death if they enter the human body. A particular danger in the use of ethylene glycol lies in the taste of such antifreeze - it tastes sweet, so you need to store such a liquid out of the reach of children.

Ethylene glycol is a clear liquid with a yellowish tint and moderate viscosity. This liquid has a very high boiling point - +197°C. But it is interesting that the temperature of crystallization, that is, freezing, is not so low, only -11.5 ° C. But when it is mixed with water, the boiling point decreases, but crystallization occurs at a lower threshold. Thus, a solution with a 40% content already freezes at -25°C, and a 50% solution at -38°C. The most resistant to low temperatures is a mixture with a glycol content of 66.7%. Such a solution begins to crystallize at -75°C.

Propylene glycol fluids are identical in properties to ethylene glycol, but they are less toxic, and they are much more expensive to produce, so they are less common.

corrosion inhibitors in antifreeze

Now for the additives used in the composition of coolants for cars. One of the most important additives are corrosion inhibitors. This type of additive, as the name implies, is designed to prevent the appearance of foci of corrosion inside the cooling system.

Several types of such liquid additives are now used, and each of them has its own designation.

The first are additives, which are called traditional, since they were the first to be used as part of antifreezes. Liquids with this type of inhibitor have no additional designation.

Traditional type inhibitors consist of inorganic substances - silicates, phosphates, nitrites, borates, as well as their compounds. Such additives form a thin protective layer over the entire inner surface of the system, preventing direct contact of the liquid with the metal.

At the moment, fluid manufacturers are trying to abandon inhibitors of this type. The reason for this is the short duration of their service life - no more than two years. An additional negative quality is the poor tolerance of high temperatures, they begin to break down at temperatures above + 105 ° C.

The second type of corrosion inhibitors that are used in coolants are carbon based organics. Liquids with such additives are called carboxylate antifreezes, their designation is G12, G12 +.

A feature of such inhibitors is that they do not form a protective layer over the entire surface. Such inhibitors chemically interact already with the corrosion site. As a result of the interaction, a protective layer is formed on top of this focus, without affecting the surface without corrosion.

A feature of this type of inhibitors is a long service life - more than 5 years, while they are immune to high temperatures.

The third type of inhibitor additives are hybrid ones. They include both carboxylate elements and traditional inorganic ones. Interestingly, by the country of origin, you can find out which inorganic elements the hybrid inhibitor contains. So, European manufacturers use silicates, American - nitrites, Japanese - phosphates.

The service life of inhibitors is higher than traditional ones, but they are inferior to carboxyl additives - up to 5 years.

Recently, another type of inhibitors has appeared - also hybrid, but they are based on organic materials, and in addition to them - mineral substances. This type of inhibitor has not yet been fully defined, so they appear everywhere as lobrids. Antifreezes with such additives are designated G12 ++, G13.

It should be noted that this classification is not quite generally accepted, it was introduced by the German concern VAG, but so far nothing else has been invented, and everyone uses this designation.

Other additives, dyes

Anti-cavitation and anti-foam additives are needed to keep the fluid in a state that will provide maximum heat removal. After all, cavitation is the formation of air bubbles in a liquid, which in the case of antifreeze will only cause harm. The presence of foam is also not desirable.

Dyes in the composition of antifreezes have several functions. It makes it easier to determine the level in the system. Expansion tanks of cars are often made of white plastic. The level of a colorless liquid in such a tank would be invisible, but having a certain shade is easily visible.

Another property of the dye is an indicator of suitability for further use. Over time, the antifreeze in the system will develop its additives, due to which the liquid itself will change color. A change in color will signal that the liquid has exhausted its resource.

As for the shades of antifreeze, they can be very diverse. Our most common colors are blue and red. And often the temperature stability of the liquid is tied to the color. So, antifreeze with a blue tint most often has a freezing threshold of -40 ° C, with red -60 ° C. However, this is not always the case; you can also purchase a liquid with a red tint, in which the temperature threshold is -40 degrees.

But these are not all the shades that antifreeze can have. There are liquids with a yellow, green, orange tint. In this matter, it all depends on the manufacturer. As for the temperature stability of antifreeze, you should not be guided only by color. For different manufacturers, this indicator may differ, despite the fact that the color of the liquid may be the same.

A few words about "Tosol"

Now about "Tosol". Almost all coolants produced by us are called that way. In fact, "Tosol" is just one type of antifreeze.

This liquid was developed at the Research Institute of Organic Chemistry and Technologies, Department of Technology of Organic Synthesis. The abbreviation of this department formed the basis of the word for liquid. The prefix -Ol in the name, according to one version, means alcohol. Hence the name - "Tosol".

"Tosol" is an ethylene glycol solution with the addition of a traditional inhibitor. It is still being produced, and there are two types - "Tosol 40" and "Tosol 65". The numerical designation indicates the freezing point of a given liquid.

Additionally, they differ in color - "Tosol 40" has a blue tint, a more frost-resistant liquid has a red tint.

In general, "Tosol", developed in the USSR, has long been outdated, but the very name of the coolant is so firmly rooted in the vocabulary that it is applicable to all liquids for the cooling system.

Features of the use of liquid

Coolant is now sold in two types - a ready-made diluted mixture, and an ethylene glycol concentrate, which must be diluted before use.

There are no problems with the use of a ready-made solution. Liquid is purchased in the amount indicated in the technical documentation for the car in the section of refueling tanks. It also indicates the type of fluid used. In this matter, it is better not to experiment, but to purchase a fluid recommended by the car manufacturer.

It is important to consider that antifreeze, like any liquid, tends to expand when heated, so you should not fill the system so that its level in the tank is “to the eyeballs”. Usually there is a label on the tank for the maximum filling of the tank, if there is none, it should not be filled more than half. It is worth saying that the level in the tank must be observed after the system is completely filled.

If a concentrate was purchased, then before pouring it will need to be diluted with distilled water. It is impossible to use the concentrate without preliminary dilution with water, do not forget that the crystallization temperature of pure ethylene glycol is not so low.

Before breeding, you need to decide on the proportions. An equivalent proportion is considered optimal - 1 to 1. Such a mixture will have a freezing point of -40 ° C, which is quite enough for most of our latitudes.

The frequency of replacing antifreeze largely depends on the chemical composition and additives. Some fluids are able to work out 250 thousand km. In general, it is believed that the resource of the liquid is 100-200 thousand km.

You should also not fully trust the manufacturers that their fluid is able to work out a significant resource. After all, this resource is indicated for a liquid filled in a completely clean engine. And when replacing a fluid, a part of the used one in the engine always remains, which, mixing with a new one, lowers its properties and affects the resource.

You should always carry a bottle of antifreeze in the car, and one that is filled into the system. Periodically, the system needs to be checked, and, if necessary, replenished.

There are times when fluid leaked from the system. In this case, you must first eliminate the leak, and then replenish the amount of liquid.

About toppings. It is impossible to mix liquids of different composition, properties and color with each other. It is not recommended even topping up with antifreeze of identical composition, but from different manufacturers.

The fact is that different manufacturers can use different additives and additives in the composition. Under conditions of high temperature and constant mixing, conflicts can arise between different additives, which can lead to different, and not always positive, consequences. They may not appear immediately, but only after a long time of using such a mixture.

Therefore, topping up should be done only with liquid from one manufacturer. If it is not possible to purchase an identical fluid filled into the system, the best option would be to completely replace the antifreeze with a new one.

But what if the liquid has leaked out, but the exact same one is at hand to replenish the level - no? As already mentioned, you cannot fill in another antifreeze. But you can add water. Antifreeze is still an aqueous solution, so water will not harm the system itself. However, it will change the properties of the antifreeze itself, the boiling point will decrease and the crystallization threshold will increase.

Such a mixture can be used in a car, but for a short time. And if the leak occurred in winter, then immediately after parking the car, it is better to drain this mixture from the system in order to avoid freezing the cylinder block. Then, before operating the car, pour new antifreeze into the cooling system.

Autoleek

Ethylene glycol (1,2-ethanediol, 1,2-dioxyethane, glycol) is the base substance for the manufacture of various antifreezes that are used in vehicle engine cooling systems.

Ethylene glycol is a toxic dihydric alcohol

The chemical formula of this simplest polyhydric alcohol is C2H6O2 (otherwise it can be written as follows - HO-CH2-CH2-OH). Ethylene glycol has a slightly sweet taste, odorless, in a purified state it looks like a slightly oily colorless transparent liquid.

Since it is classified as a toxic compound (according to the generally accepted classification, it is the third hazard class), the ingress of this substance (in solutions and in pure form) into the human body should be avoided. The main chemical and physical properties of 1,2-dioxyethane:

• molar mass - 62.068 g / mol;
• optical refractive index - 1.4318;
• ignition temperature - 124 degrees (upper limit) and 112 degrees (lower limit);
• self-ignition temperature - 380 °C;
• freezing point (one hundred percent glycol) - 22 ° C;
• boiling point - 197.3 ° C;
• density - 11.113 g / cubic centimeter.

Vapors of the described dihydric alcohol flare up at the moment when its temperature reaches 120 degrees. We recall once again that 1,2-ethanediol has a 3rd hazard class. And this means that its maximum permissible concentration in the atmosphere can be no more than 5 milligrams / cubic meter. If ethylene glycol enters the human body, irreversible negative phenomena can develop in it, which can lead to death. With a single ingestion of 100 or more milliliters of glycol, a fatal outcome occurs.

Vapors of this compound are less toxic. Since ethylene glycol is characterized by a relatively low volatility index, a real danger to a person arises when he systematically inhales vapors of 1,2-ethanediol. The fact that there is a possibility of poisoning with vapors (or mists) of the compound in question is indicated by coughing and irritation of the mucous membrane. If a person is poisoned by glycol, they should take a drug containing 4-methylpyrazole (a powerful antidote that inhibits the enzyme alcohol dehydrogenase), or ethanol (monohydric ethyl alcohol).

The use of glycol in various fields of technology

The low cost of this polyhydric alcohol, its special chemical and physical properties (density and others) have led to the fact that it is used very widely in various technical fields.

Any motorist knows what is the usual coolant for his "iron horse" called antifreeze - ethylene glycol 60% + water 40%. Such a mixture is characterized by a freezing point of -45 degrees, it is very difficult to find a more suitable liquid for automotive cooling systems, despite the high hazard class of 1,2-ethanediol.

In the automotive industry, ethylene glycol is also used as an excellent coolant. In addition, it is used in the following areas:

• organic synthesis: the chemical properties of glycol make it possible to protect isophorone and other carbonyl groups with its help, use alcohol as an effective solvent operating at elevated temperatures, and also as the main component of a special aviation fluid that reduces the phenomenon of flooding of combustible mixtures for aircraft;
• dissolution of coloring compounds;
• the manufacture of nitroglycol, a powerful explosive based on the compound we are describing;
• gas industry: glycol prevents the formation of methane hydrate on pipes, in addition, it absorbs excess moisture on pipelines.

Ethylene glycol has also been used as an effective cryoprotectant. It is used in the production of shoe polishes, as an important element of liquids for cooling computer equipment, in the manufacture of 1,4-dioxin and various types of capacitors.

Some nuances of glycol production

In the late 1850s, the French chemist Wurtz obtained ethylene glycol from its diacetate, and a little later by hydration of ethylene oxide. But at that time, the new substance did not find practical application anywhere. It was only in the 1910s that it began to be used in the manufacture of explosive compounds. The density of glycol, its other physical properties and the cheapness of production led to the fact that they replaced the glycerin that was used before.

The special properties of 1,2-ethanediol were appreciated by the Americans. It was they who established its industrial production in the mid-1920s at a specially built and equipped plant in West Virginia. In subsequent years, glycol was used by almost all the companies known at that time that were engaged in the production of dynamite. At present, the compound of interest to us, which has the third hazard class, is manufactured using the ethylene oxide hydration technology. There are two options for its production:

• with the participation of phosphoric or sulfuric acid (up to 0.5 percent) at a temperature of 50 to 100 ° C and a pressure of one atmosphere;
• at a temperature of about 200 ° C and a pressure of ten atmospheres.

As a result of the hydration reaction, up to 90 percent pure 1,2-dioxyethane, a certain amount of polymer homologues and triethylene glycol are formed. The second compound is added to hydraulic and, it is used in industrial air cooling systems, it is used to make preparations for disinfection, as well as plasticizers.

The most important requirements of GOST 19710 for finished glycol

Since 1984, GOST 19710 has been in force, which establishes requirements for what properties (freezing point, density, and so on) should have ethylene glycol used in automotive enterprises and in other sectors of the economy, where various compositions are produced on its basis.

According to GOST 19710, glycol (as a liquid) can be of two types: first grade and premium. The share (mass) of water in glycol of the first grade should be up to 0.5%, the highest - up to 0.1%, iron - up to 0.00005 and 0.00001%, acids (in terms of acetic acid) - up to 0.005 and 0 .0006%. The residue after calcination of the finished product cannot be more than 0.002 and 0.001%.

Color of 1,2-dioxyethane according to GOST 19710 (according to the Hazen scale):

• after boiling in an acid solution (hydrochloric) - 20 units for products of the highest grade (the first grade is not standardized by color);
• in the standard condition - 5 (highest grade) and 20 units (first grade).

The State Standard 19710 puts forward special requirements for the production process of the described simplest alcohol:

• only sealed apparatus and equipment is used;
• the production room must be equipped with ventilation recommended for working with compounds that are assigned the third hazard class;
• If glycol gets on the equipment or the ground, it should be washed off immediately with plenty of water;
• personnel working in the workshop for the production of 1,2-ethanediol are provided with a BKF model gas mask or other respiratory protection device that complies with GOST 12.4.034;
• glycol fires are extinguished with inert gases, special foam formulations, and water mist.

Finished products according to GOST 19710 are checked by various methods. For example, the mass fraction of dihydric alcohol and diethylene glycol is determined by the method of isothermal gas chromatography using the technology of the so-called "internal standard". In this case, scales for laboratory research (GOST 24104), a glass or steel gas chromatographic column and a chromatograph with an ionization-type detector, a measuring ruler, a microsyringe, an optical magnifier (GOST 25706), an evaporating cup and other tools are used.

The color of the glycol is set according to standard 29131 using a stopwatch, a special cylinder, a conical flask, hydrochloric acid, a refrigeration unit. The mass fraction of iron is determined according to State Standard 10555 using the method of sulfacyl photometry, the residue after calcination is determined according to State Standard 27184 (by evaporating the resulting compound in a platinum or quartz container). But the mass fraction of water is determined by electrometric or visual titration using Fisher's reagent in burettes with a capacity of 10 or 3 cubic centimeters.

Antifreeze - glycol based coolant

Antifreeze based on the simplest multivolume alcohol is used in modern vehicles to cool their engines. Its main component is ethylene glycol (there are formulations with propylene glycol as the main component). The additives are distilled water and special additives that give antifreeze fluorescent, anti-cavitation, anti-corrosion, anti-foam properties.

The main characteristic of antifreezes is a low freezing point. In addition, they have a low rate of expansion upon freezing (compared to 1.5-3 percent less than ordinary water). At the same time, this special glycol-based coolant is characterized by a high boiling point, which improves the operation of the vehicle in the hot season.

In general, a glycol-water based engine coolant has the following advantages:

• the absence of harmful additives (amines, various nitrites that adversely affect the nature of phosphates);
• the ability to select the required concentration of antifreeze for high-quality protection against freezing;
• stable parameters and properties throughout the entire service life;
• compatibility with those parts of the auto cooling system that are made of plastic or rubber;
• high antifoam performance.

Among other things, modern antifreezes provide anti-corrosion protection of metal alloys and metals present in an internal combustion engine due to the presence of special inhibitory additives in them.

In this article we will tell you what automotive antifreeze is, how it differs from antifreeze and what is the service life. Effect on engine overheating.

What's the Difference?

Antifreeze- the name of the antifreeze developed for VAZ cars. The Tosol trademark has not been registered, so it is used by many domestic manufacturers of coolants. The name arose like this: the first 3 letters were taken from the name of the department where it was made: “Technology of Organic Synthesis”. And the ending "ol" came from the chemical industry and indicates that the products belong to alcohols.

As a result, "TOSOL" appeared, which was intended for the first Zhiguli cars. Over time, the name from the abbreviation ("TOSOL") turned into a household name - this is how motorists began to call any coolants. Do not succumb to the delusion that antifreeze is intended for Russian cars, and antifreeze for foreign cars. Antifreeze is one of the antifreezes.

What are they made of?

antifreeze- coolants of the car cooling system that do not freeze at low temperatures. They consist of dihydric alcohol - ethylene glycol (65%), water (35%) and anti-corrosion additives, which chemists call inhibitors - corrosion retarders. Manufacturers give them their own names ("Tosol", "Lena") or indicate the freezing point (OJ-40).

The basis is a glycol-water mixture, on which they depend: the ability of antifreeze not to freeze at low temperatures, its specific heat capacity, viscosity and effect on rubber. The most common antifreeze based on ethylene glycol. But its aqueous solution is aggressive to the materials of the cooling system parts (steel, cast iron, aluminum, copper, brass, solder).

Therefore, a complex of additives is added to the coolant: anticorrosive (inhibitors), antifoaming and stabilizing.

There are many standards: in Russia it is GOST 28084-89 (which is obsolete), in the USA - ASTM D3306, D4340, D4656 (constantly updated), in England - BS 6580. They determine the characteristics of antifreezes: density, crystallization onset temperature, corrosive effect on metals, impact on rubber, resistance to hard water - and regulate tests for their verification. But they do not specify the composition and concentration of additives, as well as the miscibility of liquids. This, as well as the color of antifreeze (blue or yellow), is chosen by the manufacturer.

There are no GOSTs regulating the service life of antifreeze and the conditions for resource tests. In practice, manufacturers use technical specifications (TS), entering the necessary information into them. Therefore, antifreezes often appear in stores, freezing at -25 ° C and boiling at 90 ° C. Officially, the boiling point of antifreeze should be in the range of 105-115 ° C.

In addition to general standards, many manufacturers apply specifications with additional requirements. For example, the Volkswagen Group's regulatory system, which standardizes antifreezes labeled G11, G12 and G13. Many chemical companies and trade representatives began to use their compact names to classify coolant.

What is the service life?

During operation, antifreeze ages - the concentration of inhibitors gradually decreases, heat transfer decreases, the tendency to foaming increases, and unprotected metals corrode intensively. The resource depends on the quality of antifreeze and the mileage of the car.

The replacement period is prescribed by the car factory or manufacturer. Usually change every 2-3 years. On modern machines, they change during operation for more than 5 years or 250,000 kilometers. For example, Volkswagen adheres to such a schedule for new cars. AvtoVAZ indicates a change after 75,000 km or 3 years, when using such antifreeze. Next, we list the signs when the coolant is aging earlier:

• a jelly-like mass is formed on the inside of the neck of the expansion tank, at slight negative temperatures (minus 10-15 ° C), clouding is noticeable in it (like a light cloud), a precipitate forms, and the radiator electric fan also works more often. When at least one of these signs appears, the antifreeze should be changed as soon as possible;
• the color becomes reddish-brown. This means that the parts of the system are already corroding. Such fluid must be replaced immediately, regardless of how long it has served.

Can you mix?

Domestic liquids produced by different manufacturers according to the same specifications can be mixed. If the specification numbers are not the same, antifreezes are often incompatible. The components of additive complexes can react with each other and lose their useful properties. Therefore, in a hopeless situation, it is better to add water, and then replace all the fluid in the system.

If the color is different. For example, the old one is yellow, but you are going to fill in red antifreeze. Can you mix? Read more in this article.

Effect on engine overheating

Boiling point of antifreeze - not less than 105°С if it complies with all standards and GOSTs. It happens that manufacturers try to save on products and instead of expensive ethylene glycol they add cheaper glycerin, which costs a penny. Glycerin-based antifreeze becomes viscous, as a result, the motor overheats.

So that it does not freeze at -25 ° C, manufacturers add methanol, which significantly reduces the freezing point. The boiling point of methanol is only 65.5°C. At higher temperatures, methanol begins to actively evaporate and reduces the boiling point of antifreeze to 85-90°C instead of the prescribed 105-108°C.

Leaks of low-quality antifreeze lead not only to overheating of the engine, but also to a fire. Get methanol, for example, on a hot collector - open burning may occur.

Not always, the addition of glycerin to the composition indicates low-quality antifreeze. For example, Volkswagen, in the production of G13 coolants, adds a small percentage (up to 20% in concentrate) of glycerin to the composition. This is done not for the sake of economy, but thanks to the environment. Glycerin is a by-product in the production of biodiesel, which means it needs to be put somewhere - for example, used in antifreeze.

We advise you to purchase antifreeze at branded points of sale or through official suppliers in online stores. If you bought a fake, then in winter it will lead to a poor start of the engine in cold weather, and in summer - to a fire in the engine compartment.

In addition to the general standards, many car manufacturers apply their own specifications, with additional requirements. For example, General Motors USA standards

Antifreeze Concentrate GM 1899-M, GM 6038-M,
or the Volkswagen G regulation system:
- G 11 - for cars or light trucks (inorganic additives, the presence of silicates is allowed);
- G 12 - for heavy equipment or new vehicles (organic additives, include carboxylate compounds, no silicates).

Information about the absence of silicates (free of silicate or silicate free) is important when using coolant in heavy equipment engines. At high temperatures, silicates can turn into gel-like deposits that clog the narrow channels of the cooling system. Such documents often prohibit the introduction of corrosion inhibitors containing nitrites, nitrates, amines, phosphates into antifreeze, and stipulate the maximum permissible concentrations of silicates, borax and chlorides. Nitrite-nitrates, interacting with amines, form toxic compounds, and some of them are carcinogenic. Limiting the content of phosphates, silicates, borates reduces scale deposits in the cooling system, increases the life of the water pump seals (less insoluble deposits), improves protection against cavitation corrosion (for more details on the characteristics of additives, see the corresponding paragraph of the chapter).

In Russia, the word historically synonymous with the word antifreeze is antifreeze. Often, antifreeze is understood as an imported analogue of antifreeze. Actually the word "TOSOL" itself is the name of the first automotive antifreeze, designed specifically for use in the Zhiguli cooling system and widely known.

TOSOL is designed to cool car engines at any time of the year at any temperature, up to minus 65°C. Outwardly, the standard TOSOL-40 is a blue liquid, TOSOL-65 is red, however, the color is only a matter of the manufacturer's preferences, which does not affect the properties in any way. So, in Germany, antifreeze is dark green, and in Italy it is red. The main purpose of coloring modern coolants is to inform the consumer about the composition of the coolant - the organic basis of the additive package or inorganic - in order to determine the possibilities of mixing different coolants.

In Russia GOST 28084-89 “Low-freezing cooling fluids. General technical conditions» normalizes the main indicators of coolants based on ethylene glycol (concentrate, coolant-40, coolant-65): appearance, density, crystallization onset temperature, corrosive effect on metals, foaming, rubber swelling, etc. But he does not specify the composition and concentration of additives, as well as the miscibility of liquids. This, as well as the color of the coolant (blue, green, yellow, etc.), is chosen by the manufacturer. There are no GOSTs regulating the service life of antifreeze and the conditions for resource tests yet. Technical certification of the coolant is optional. Technical requirements for antifreezes are set out in TTM 1.97.0717-2000 and TTM 1.97.0731-99.

Technical requirements for various types of coolants for the most popular liquid in central Russia with a freezing point of minus 40 ° C according to GOST 28084-89 are presented below.

Table 1.3.

Technical characteristics of coolants (according to GOST 28084-89)

Name of indicator	Norm according to GOST 28084-89
1. Appearance	Transparent homogeneous colored liquid without mechanical impurities
2. Density, g/cm 3 , at 20 o C, within	1,065-1,085
3. The temperature of the beginning of crystallization, o C, not higher	minus 40
4. Fractional data:
distillation start temperature, o C, not below	100
mass fraction of liquid distilled before reaching a temperature of 150 o C,%, not more than	50
5. Corrosive effect on metals, g/m 2 day, not more than:
copper, brass, steel, cast iron, aluminum	0,1
solder	0,2
6. Foaming capacity:
foam volume, cm3, no more	30
foam stability, s, no more	3
7. Rubber swelling, %, no more	5
8. Hydrogen index (pH), within	7,5-11,0
9. Alkalinity, cm3, not less	10

Areas of application for antifreeze

Antifreezes in general are widely used in various applications. The main direction of use is liquid cooling of internal combustion engines. This sector includes the use of coolants in cars and trucks with petrol and diesel engines.

In addition, coolants are used in agricultural, construction and other special equipment, as well as in military equipment. In these areas, vehicles with diesel engines are predominantly represented.

Coolants are also used in motorcycle engines, but this sector is much less capacious. It should be noted that specialized coolants are produced for motor vehicles, which are not currently produced in Russia.