Density of antifreeze. How to measure and what does it affect?

Antifreeze is the most famous domestic antifreeze for car cooling systems. When choosing this substance, it is necessary to evaluate a number of its parameters. First of all, this is the quality of the product on sale. The correct operation of the vehicle systems and their durability will depend on this.

The density of antifreeze is one of the most important characteristics, which allows the buyer to evaluate its performance qualities. After all, antifreeze compliance with modern requirements is a guarantee of the correct operation of all mechanisms.

General characteristics and composition

To understand how to measure the density of antifreeze and antifreeze, you need to understand their characteristics and definition. The presented substance is needed to cool the engine in summer and protect it from mechanical destruction in winter.

The name of antifreeze is based on an abbreviation. TOS – technology of organic synthesis. The last two letters of the name indicate that the substance belongs to the group of alcohols, which, as is known, end in “ol”.

The basis of antifreeze is glycol ether. The composition includes about 10 different additives. Thanks to this, antifreeze is not susceptible to frost or heat, does not boil or foam. Special additives eliminate the impact on mechanism materials, making them non-corrosive. Antifreeze can also be stored and used for a long time due to its special composition.

Antifreeze A40M - features and advantages of coolant

How to drain all the antifreeze in a VAZ 2114 engine. Drain all the coolant from the system. drain antifreeze or antifreeze from the radiator

A more modern brand of antifreeze is antifreeze A40M, which has all the advantages of A40 and provides high-quality protection of the car engine cooling system from corrosion. Below we present the general characteristics of this composition:

• good anti-foam and lubricating properties;
• absence of any chemical reactivity upon contact with engine parts;
• low viscosity and good density;
• increased thermal capacity and conductivity;
• low temperature during freezing;
• high resistance (chemical) during storage and use.

Due to all these features, antifreeze A-40M when used is described by the following advantages: the engine does not overheat; the car cooling system is under reliable and constant protection against corrosion; the motor functions “like a watch” for a long time; the possibility of ignition of the composition is eliminated (its boiling point is 100 degrees or more).

It should also be noted that the A40M and A40 trains are ready for use immediately after their purchase. There is no need to stir anything, add water to them, or perform other actions.

What characterizes density?

The density of antifreeze can tell a lot about the state of this substance during operation. Therefore, it is required to check it regularly. This indicator is influenced by several main factors. First of all, this is the composition and recipe for the production of antifreeze. Each manufacturer uses a specific technology in the production of its refrigerant.

The second important factor is the quantity and set of additives. These components improve the performance of antifreeze and additionally protect systems and mechanisms from premature wear. During the production process, technologists use a certain set of these additional components. They are clearly balanced. Some of them are incompatible and depend on the operating conditions of the equipment.

The last important factor that affects the density of antifreeze is the amount of monoethylene glycol in it. All these features affect heat capacity and thermal conductivity. If the density of antifreeze changes, this can lead to dire consequences.

Methods and means of measurement

Many drivers use antifreeze due to its property of not freezing at low temperatures.
This advantage allows you to use it even in the most severe frosts. But such a liquid has a certain period of operation and this depends on its density, the low level of which, after prolonged use, affects the frost resistance of antifreeze. To measure the density of the coolant, you need to use a hydrometer (another name for a densimeter). This device, together with a conventional thermometer, will be able to establish certain antifreeze levels in your engine.

This procedure has several stages:

• the engine temperature should be no more than 20 degrees (it can be measured with a regular thermometer);
• open the radiator or expansion tank to collect fluid;
• use a hydrometer to collect a certain amount of substance;
• place the device vertically to measure the concentration of antifreeze;
• Compare the hydrometer readings with those indicated on the packaging.

How to measure density yourself?

When considering how to check the density of antifreeze, you should pay attention to the simplest methods. Special equipment helps to take measurements for any liquid. This device is called a hydrometer. It is easy to use. In this case, only a few simple steps are performed.

First, open the hood. Next, you should find the expansion tank, which contains the antifreeze. Its lid opens. The required amount of antifreeze is taken with a hydrometer. To do this, a pipette is lowered into the refrigerant and the substance is drawn into the flask. The float must balance freely.

It is necessary to measure the antifreeze concentration on the hydrometer scale. Next, the obtained result is compared with the nominal value specified by the manufacturer. In some cases, the density may be lower or higher than stated. This can also be affected by the amount of water in the solution.

Optimal antifreeze density

If the device does not have a graduated scale and temperature values, then the density readings will tell the car owner almost nothing. But if such a scale exists, then it is necessary to control the quality of the coolant in terms of density by comparing it with standard data.

Modern manufacturers of cooling products for cars market anti-freeze products with a density of 1.069 - 1.072 g/cm 3 and a freezing temperature of less than 40 degrees below zero. It is necessary to take into account a certain factor that dihydric alcohol dissolved in water freezes at minus 40 with saturation indicators of 1.071 and 1.104 g/cm 3 .

At the manufacturing plant, the determining factor in the choice between two liquid densities will be 1.071 g/cm 3, since the characteristics of the coolant will not be lost, and in manufacturing it will be more profitable for the company.

Measurement result

Now you know how to check the density of antifreeze with a hydrometer, now you need to understand the result obtained.

The density indicator is affected by the water used to dilute antifreeze in a factory or at home. As its content in the solution increases, the freezing point of the substance becomes higher, and the cooling characteristics deteriorate in the summer.

If the density of a substance is underestimated when measured, this means that the antifreeze contains a large amount of water. In this case, the operating temperature range of antifreeze becomes narrower. This is a negative trend.

An increased concentration indicates a decrease in the cooling and lubrication properties of mechanisms. Because of this, they wear out quickly. Therefore, it is necessary to compare the nominal density value stated on the packaging with the hydrometer readings. If necessary, it is adjusted.

Useful tips

As experts advise, if antifreeze is purchased in the form of a concentrate, after pouring the finished liquid into the cooling system, be sure to measure the density of such a composition. If you purchased ready-made antifreeze or antifreeze, you must immediately measure its density before pouring it into the system.

The fact is that there are a large number of counterfeits of well-known brands of coolants on sale (Shell, Liqui Moly, Bizol, etc.). Simply put, there is no ethylene glycol/propylene glycol. Instead of the base, acids and sugar and salt are used.

The danger of such products is that initially measuring the density may show the norm, and the liquid will not freeze in the cold. However, after a short period of time after heating and cooling, the fake antifreeze will lose its properties and freeze in slight frost with all the ensuing consequences.

We also recommend reading the article on how to drain antifreeze from the engine block and radiator of a car. From this article you will learn about the features that need to be taken into account when draining and replacing coolant in the internal combustion engine cooling system.

To avoid such risks, it is better to check the density of the liquid again a couple of days after replacing the antifreeze. If there are obvious changes in the direction of decreasing density, then it is a fake. It is urgent to drain such antifreeze, thoroughly flush the entire cooling system and refill with a high-quality original product.

In practice, it is ready-made antifreeze (already mixed with water) that is most often counterfeited, but similar manipulations with the concentrate also cannot be ruled out. For insurance, we can recommend purchasing antifreeze, antifreeze and other technical fluids exclusively at official or verified points of sale.

Normative value

One of the most popular types of the substance presented is antifreeze brand A-40 or A-40M. This refrigerant is used in relatively warm climates where the temperature in winter does not drop below -38°C. Among car enthusiasts in our country, it is widely believed that the density of antifreeze A-40 is 1.075 g/cm³. In this case, the mixture contains about 44% water and 56% ethylene glycol (or higher).

The density indicator depends on the temperature at which the measurement was taken. Standards set the permissible norm of this value at 1.065-1.085 g/cm³. In this case, the ambient temperature should be at +20°C.

If the number obtained during measurements does not correspond to this indicator, it can be adjusted. To do this, drain off a little old antifreeze and add either water or antifreeze concentrate to the overall mixture.

Dependence of antifreeze density on temperature

A simple rule works here: as the temperature decreases, the density of antifreeze increases. Let's briefly look at the example of antifreeze A-60.

At temperatures close to freezing (–60 °C) the density will fluctuate around 1.140 g/cm³. When heated to +120 °C, the density of antifreeze will approach 1.010 g/cm³. That is, almost like pure water.

The so-called Prandtl number also depends on the density of antifreeze. It determines the ability of the coolant to remove heat from a heating source. And the greater the density, the more pronounced this ability is.

Lifetime

Knowing what density of antifreeze currently affects the car’s systems, as well as what the standard value of this indicator is, you can avoid premature repairs or car breakdowns. Over time, antifreeze ages. Its service life depends on the quality of the antifreeze itself and the mileage of the car.

If the density of the mixture is low, there is a large amount of water in the solution. It impairs the effect of additives and provokes the formation of corrosion. This leads to rapid destruction of the surfaces of mechanisms. In this case, the liquid takes on a rusty tint. Regardless of the service life of such a substance, it should be replaced immediately with new antifreeze.

Low antifreeze level

What is better antifreeze or antifreeze?

One of the reasons for antifreeze boiling may be its lack in the system. This happens when the cooling system charge level is insufficient. The filling arrow on the tank body should be between o and “max”.

Low coolant levels can occur when there is a coolant leak. And given that the boiling point of antifreeze at pressure is higher than in a depressurized system, the combination of these factors becomes the cause of an emergency.

Leaks happen anywhere. It needs to be found and eliminated. Any damage to components of cooling structures must be repaired immediately.

How to change antifreeze

If you have measured the density of antifreeze, assessed its visual characteristics and determined the need to replace this substance, you need to carry out a special procedure. Warm up the engine for 5 minutes. The heater valve in the cabin must be open. After stopping the engine, the old antifreeze is drained and clean water is poured in instead. You can use a special cleaning agent. It is used in accordance with the manufacturer's instructions.

Through the drain plug, which is located in the radiator, water is removed from the system. Rinsing is done until the liquid becomes clear. After this, you can fill in new antifreeze.

Having studied what the density of antifreeze is, you can understand the importance of measuring it. This indicator will allow you to evaluate the correct operation of the entire system and prevent its breakdown.

Antifreeze "Alaska" A-40

This product is manufactured by Tektron LLC. The manufacturer claims that it produces the best antifreeze on the market. But reviews prove the opposite. This antifreeze does not meet the stated characteristics. And if the crystallization temperature still meets the norm (-41 degrees Celsius), then this liquid already boils at 100 degrees Celsius. In view of this, it is dangerous to use such a liquid even on VAZs of the 2000s. But for “Classics” it will still work. The foam stability and foaming properties are 1.5 and 20, respectively. The pH value is 8.1 pH. The experts' conclusion is this: the fractional composition of this brand of antifreeze does not meet the standard.

About the operation of the cooling system

Often while driving, especially when it is hot outside, the antifreeze in the expansion tank boils. Why this happens and how to fix it is of primary interest to the car owner. To eliminate the malfunction, you need to understand how the cooling system works. Otherwise, it will be quite problematic to identify the cause of the problem and fix it on the spot.

When starting the engine, it is in an unheated state. Therefore, antifreeze circulates only in a small cooling circle. It includes:

• engine water jacket;
• stove;
• thermostat.

At this moment, the liquid level in the tank is within normal limits. As the power unit warms up, a large circulation circuit begins to open, passing through the main radiator. This leads to the fact that the volume of technical fluid in the system expands. Its excess ends up in the tank. As the pressure increases, it is partially relieved using a bypass valve. It is present on the lid of the working container.

When antifreeze reaches a temperature of 95 degrees Celsius, it increases in volume to maximum values. Its excess is discharged through the upper radiator pipe. For this reason, many motorists have the impression that antifreeze is boiling in the expansion tank. Any experienced car enthusiast can explain why this happens.

Depending on the design of the system in a particular car, the cap with the valve can be installed either on the radiator neck, or placed directly on the tank. In the second case, the release occurs only after the pressure has risen. This working vessel communicates with the atmosphere through an opening present in the plug.

A little physics

It is incorrect to talk about the boiling point of antifreeze in the specifics of antifreeze, since, firstly, antifreeze has a certain chemical composition, and its thermophysical characteristics are determined not only by temperature, but also by pressure. Secondly, antifreeze, which at one time was created exclusively for domestically produced engines, contains additives that ensure not only the operation of the car at low temperatures, but also its protection from a number of unfavorable factors:

• corrosion;
• wear;
• cavitation.

Antifreeze, unlike antifreeze, does not have a lubricating effect, and wear reduction is achieved due to a decrease in the temperature of the moving elements of the drive, with an increase in which the gaps are selected and the friction coefficient naturally increases.

If everything is more or less clear with the permissible temperature (no more than 90ºС), then with the pressure in the engine the situation is more complicated. To protect the engine from overheating, antifreeze is pumped at elevated pressures, which also affects the temperature of the liquid. For most brands, the actual pressure in the cylinder block is at least 1.2...1.3 at: it is then, according to the Clausius law, that the maximum temperature required for boiling liquids increases. Thus, the theoretically permissible boiling point of coolants can be 110...112ºС.

Density of some types of liquids, table kg/m3

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Coolants and their types

Almost all antifreezes contain water and special additives. The basis of any coolant can be:

• Propylene glycol - if you compare it with other types of antifreeze, this substance does not cause any harm to human health, not only through direct contact, but even when its vapors are inhaled. The main advantage of this type of antifreeze is its safety. That is why it is actively used in double-circuit heating systems, since even if the substance gets into the hot water circuit, nothing bad will happen. In addition, propylene glycol is used as an agent in the confectionery industry, and is also a food additive. Propylene glycol is usually green in color. Due to the availability of different colors of antifreeze on sale, confusion arises as to whether antifreeze of different colors can be mixed or not. It all depends on the purpose and operating conditions. Like other antifreezes, the freezing point of propylene glycol is around -35 C.
• Ethylene glycol is a very popular type of antifreeze, mainly due to its low market price, and in addition, it is available in two types: with freezing points of -30 ° C and -65 ° C. Its main drawback is the increased danger to human health. Therefore, this brand of antifreeze is red in color, so that in case of a leak it is noticeable and its consequences can be quickly eliminated.
• Triethylene glycol is a less commonly used antifreeze, mainly in systems where temperatures are high. Triethylene glycol is considered a special antifreeze.

Therefore, when choosing which brand of antifreeze you need, it is better to resolve this issue before starting construction of the house.