10W-40: transcript. What do the numbers "10W-40" on motor oil mean?

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

In the history of the automotive industry, there has never been a better way to protect an engine than engine oil. And although for more than a century of history, its composition has been constantly updated, the principle of operation remains the same - ensuring the proper slip coefficient between engine elements with surface cooling. One commonly used type is 10W-40 oil. The interpretation of this designation gives complete information about the characteristics of the liquid.

Scope of application

For a better understanding of the rules for the use and choice of engine oil, you need to learn more about the principle of its effect on engine parts.

During the operation of the power unit, friction processes inevitably occur between its elements. This applies in particular to the movement of pistons in cylinder heads and crank mechanisms. This creates high temperatures that adversely affect the material and can lead to rapid wear.

Motor oil is a kind of liquid gasket between them. As soon as the engine starts and the first batch of fuel burns out, the oil underthe action of moving parts is evenly distributed over the surface. This is an exaggerated characteristic, since a complete description in detail of the entire process in most cases is necessary only for specialists. It is important for the consumer to know not only what 10W-40 means, but also the main parameters:

• Composition.
• Temperature limits.
• Viscosity.

According to engine parameters and external factors, the most suitable 10W-40 oil is selected. Decryption will give complete information about these characteristics.

Composition

The ideas for using engine oil were laid down at the design stage of the first internal combustion engines. Before the development of the chemical industry, only one type of it was known - mineral. The composition includes natural components that are obtained as a result of oil refining. But its properties do not always correspond to external conditions and engine characteristics. The disadvantages of mineral oil are:

1. Change in the viscosity coefficient when limiting temperatures are reached (both minus and plus).
2. Relatively low shelf life. The longer the oil is in the engine, the more its internal structure changes. This leads to the loss of positive properties.

Affordable cost can be considered an undoubted advantage.

In the second half of the twentieth century, a new type of oil appeared - synthetic. It comes from the aviation industry. Received as a result of complex synthesis, the remedy quickly became popular.

Special design for starting aircraft engines at low temperatures found its way into the automotive industry. Therefore, 10W-40 engine oil has the following benefits:

1. Large operating temperature range.
2. Long service life without loss of properties.
3. Unique viscosity parameters that are unique to this type of engine oil.

In order to reduce the cost, manufacturers have developed an intermediate option - semi-synthetic types. This is the result of mixing the above types of lubricants.

Transcript

Now that the main types are known, we can proceed to a detailed description of the characteristics of 10W-40 oil. The decoding of this designation consists of several indicators.

• 10W indicates the preservation of the viscosity parameter at a minimum temperature of -25 °C.
• 40 – upper high temperature limit (up to +40°С).

In fact, when the manufacturer indicates such data on the packaging, he informs the consumer about the operating limitations of a particular type of oil. How is this actually reflected in the operation of the power plant in the event of a discrepancy between the recommended temperature regimes and the required ones?

Misuse of operating conditions

Reducing the temperature below the limit level leads to an increase in density. In this case, problems may arise with starting the engine - the oil will not be evenly distributed over the surfaces. It is possible to quicklywear or failure of the power unit. Therefore, it is extremely important to know what information this oil decoding contains - 10W-40.

As the temperature rises, the density of the oil critically decreases. It is no longer able to perform its functions, since the viscosity coefficient does not make it possible to create a homogeneous film. Most of the lubricant settles in the crankcase. At a constantly high temperature, partial evaporation of the liquid occurs. A characteristic feature of this phenomenon is the dimming of exhaust gases and an increase in their volume. It also leads to quick breakdowns.

Classification

It is necessary to select the brand of oil depending on the application. Currently, they use the international standard API - American Petroleum Institute. According to it, a separate classification has been adopted for gasoline and diesel engines. The main difference is in the years of production of car models.

Therefore, to select a lubricant, it is not enough to know what the numbers on 10W-40 oil mean. In addition to these data, classification must be taken into account. For modern cars, the markings indicated in the table are accepted.

Designation	Years of issue	Specific application
Petrol
SG	1989-1994	Using conditions as harsh as possible
SH	1995-1996
SJ	1997-2000	To improve energy saving properties
SL	2001-2003	Increases service life
SM	Since 2004	Improved oxidation resistance
Diesel
CG4	C 1994	For cars with turbines
CH4	C 1998	Designed to reduce toxicity (USA)
CI4	Modern	With turbine and EGR valve installed

Sometimes there are brands that can be used for all types of power units, regardless of the type of energy carrier.

Quality settings

After choosing the type of oil that is as close as possible to real operating conditions, you need to make sure of its quality. Two different methods can be used for this:

• Experimental. Through much trial and error, find a really high-quality 10W-40 oil.
• Learn more about the API classification.

The latter method is more acceptable, as it does not pose a potential threat to engine operation. Every year, API representatives evaluate new brands of lubricants. Depending on the results, they are assigned a certain index.quality.

Eight designations are accepted for gasoline - A, B, C, D, E, F, G, H. For diesel there are six of them - A, B, C, D, E, F4. Therefore, when buying, you need to pay attention to the letter - the farther it is from the beginning of the alphabet, the better the quality.

Additives

To improve the properties of the lubricating fluid, special chemical components are used. They received the general name of additives. Therefore, sometimes it is not enough to know the basic properties of 10W-40. The decoding of the full characteristics of the manufacturer is indicated on the package, including the type of additive, its technical parameters and content.

There are many different types of additives. Some of them are added directly by the manufacturer, some are sold separately for independent use.

The most popular at the moment are the following types:

• Increasing the viscosity index.
• Removing combustion products from the inner surface of the engine.
• Increasing wear resistance.
• Preventing the development of oxidative processes.

Before adding each of them, you should carefully read the instructions for use. After all, in addition to the positive effect, there may be side effects.

Tips

In order for the engine to work out the prescribed resource and in order to avoid unforeseen breakdowns, it is recommended to follow the following tips for choosing oil:

1. Before purchasing, please check withcar manufacturer's recommendations.
2. It is mandatory to change the oil according to the manufacturer's schedule. For urban conditions, when driving in low gears, lubricant consumption increases. It is best to have a periodic check in a specialized service station.
3. Before filling in any 10W-40 engine oil, flush the engine. This will increase the energy resource and eliminate the possibility of performance degradation.

Experienced motorists are always guided by these rules - just make a schedule for the technical inspection of the car.

Having learned the specifics of the name of motor oils, you can safely choose the right type of lubricant. Given the large number of manufacturers, this can be quite difficult to do. It is important for every car enthusiast to know what 10W-40 means. Therefore, it is necessary to take this issue responsibly - the cost of repairing a car is disproportionately higher than the price of good oil.