The API (American Petroleum Institute) engine oil classification system has been in existence since 1969. Its main purpose is to separate motor oils by quality and the technology used.
In accordance with these categories, the appropriate designations are used in the names of the respective standards. For example, oils so standardized are usually referred to as API SE. Now we will analyze in more detail what these letters mean.
Each new class is assigned an additional alphabetical letter. Universal oils for gasoline and diesel engines are indicated by two symbols of the corresponding categories: the first symbol is the main one (indicates which engine the oil is for), and the second indicates the possibility of using it from the year the engine was created, and whether it has a turbine or not.
S (Service) - consists of quality categories of motor oils for gasoline engines, going in chronological order.
C (Commercial) - consists of categories of quality and purpose of oils for diesel engines, going in chronological order.
If the oil passes several standards, for example, API SJ / CF, then it is suitable for both gasoline and diesel engines of this category. The figure below shows all the main oil standards in the API category.
Based on these two tables, we will talk about the most popular categories today.
Petrol oils
The category was approved on 11/06/1995, licenses began to be issued from 10/15/1996. Automotive oils in this category are designed for all currently used gasoline engines and completely replace the oils of all previously existing categories in older engine models. The maximum level of operational properties. API SJ/EC Energy Saving Certification Possibility.
Introduced in July 2001 for multi-valve turbocharged engines equipped with exhaust control and aftertreatment systems. API SL implies the following engine oil improvements:
- reduced exhaust emissions
- protection of exhaust control and neutralization systems
- increased wear protection
- enhanced protection against high temperature deposits
- extended drain interval
Entered into force in November 2004. API SM includes engine oils for gasoline engines manufactured after 2004. Engine oils that meet the requirements will provide reliable lubrication for turbocharged and multi-valve engines. API SM certified motor oil may have an additional ILSAC GF-4 specification, which indicates the high energy-saving properties of the motor oil.
(not in the table) - entered into force in October 2010. Today, these are the latest (and therefore the most stringent) requirements that apply to manufacturers of motor oils for gasoline engines. Certified oils imply the possibility of use in all modern generation gasoline engines (manufactured after 2010).
Important in the emergence of the API SN class of the API classification can be noted the introduction of the following requirements
- Can be used in engines using biofuels;
- All standard oils are energy-saving;
- Increased requirements for ensuring engine wear resistance;
- API SN engine oils are supposed to provide a "long and happy life" to emission control systems and an "eco-friendly" exhaust.
Diesel oils
CF - introduced in 1994. Oils for off-road vehicles, engines with split injection, including those running on fuel with a sulfur content of 0.5% by weight and above. Replaces CD oils.
CF-2- Introduced in 1994. Improved performance, used instead of CD-II for two-stroke engines. The highest oil for two-stroke engines.
CF-4 - introduced in 1990. For high-speed four-stroke diesel engines with and without turbocharging. Can be used instead of CD and CE oils. Higher for four-stroke engines.
CG-4 - introduced in 1995. For high-speed diesel engines operating on fuel with a sulfur content of less than 0.5%. CG-4 oils for engines that comply with the exhaust gas toxicity requirements introduced in the USA since 1994. Replaces CD, CE and CF-4 oils. Higher for models since 1995.
CH-4 - introduced in 1998. For high speed 4-stroke engines that meet U.S. emission regulations since 1998. CH-4 oils allow the use of fuels with a sulfur content of up to 0.5% by weight. Can be used instead of CD, CE, CF-4 and CG-4 oils.
CI-4 - introduced in 2002. For high-speed four-stroke engines designed to meet the 2002 exhaust emission regulations. CI-4 oils allow the use of fuels with a sulfur content of up to 0.5% by weight, and are also used in engines with an exhaust gas recirculation (EGR) system. Replaces CD, CE, CF-4, CG 4 and CH-4 oils. In 2004, an additional API category, CI-4 PLUS, was introduced. The requirements for soot formation, deposits, and viscosity indicators have been tightened.
CJ-4 - Introduced in 2006. For high-speed four-stroke engines designed to meet the 2007 emission regulations on highways. CJ-4 oils allow the use of fuels with sulfur content up to 500 ppm (0.05% by weight). However, operation with fuels containing more than 15ppm (0.0015% by weight) sulfur may affect the performance of exhaust aftertreatment systems and/or oil change intervals. CJ-4 oils are recommended for engines equipped with diesel particulate filters and other aftertreatment systems.
Internal combustion engines of different years of manufacture have design features that require the use of certain types of lubricants. To classify motor oils, several standards are used that have different requirements and basis, which affects lubrication characteristics.
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Types of motor oils
Motor oils are divided into several categories based on the base, which determines the viscosity of the fluid. This indicator has a direct impact on the lubricating characteristics of the substance. The viscosity must remain within certain limits when heated, since an overly fluid liquid will be unable to form a protective film.
Synthetic engine oils
The basis of the oil is obtained by the synthesis of various chemical compounds. The synthetic base provides many of the characteristics of the lubricant, so the amount of additives is negligible.
Synthetics provide car owners with a number of advantages:
- Extended service life, which can reach up to 30 thousand kilometers. During operation, the oil does not lose its characteristics due to waxing and oxidation.
- Low viscosity for improved lubricity.
- Suitable for operation at low air temperatures (minus 30 ºС and below). Cold oil is well pumped by the pump through the lines, providing lubrication at the time of starting the engine.
- Withstands overheating without noticeable performance degradation. When heated, only a small part of the oil evaporates.
- Low ash content, which leaves a small amount of soot and deposits on engine parts.
The only drawback of synthetic motor oils is the price, which averages about 600 rubles. per litre.
Semi-synthetic engine oils
A compromise between price and performance is a semi-synthetic oil. The lubricant consists of mineral oil and synthetic components. Due to this composition, it is possible to obtain a liquid that has a low price and parameters close to synthetics.
Mineral engine oils
They belong to the category of oils of the lower price range. It is based on hydrocarbons obtained by oil hydrocracking. The disadvantage of the mineral substance is a low resource and inability to work at high temperatures.
Flushing motor oils
Another type of motor oil is flushing, which can be mineral or synthetic based. Additional components are introduced into the composition of the liquid, which allow washing off the resinous deposits that form on engine parts. are also used when switching to another type of lubricant or to a liquid with a different classification. This substance is poured for a short time, after which it is drained and must be disposed of.
Classification of motor oils
There is no single standard for the classification of motor oils. Different manufacturers may use international specifications that correlate with each other, or their own.
The most common classifications are:
- ACEA.
Features of the classification of motor oils
Depending on the classification, oils are divided according to various parameters:
- viscosity;
- year of manufacture of the engine;
- operating conditions.
In addition, many automakers develop their own requirements. Oil manufacturers adapt their products to these standards, which is reflected in the designation. When using a lubricant, make sure that the characteristics of the fluid meet the requirements of the vehicle manufacturer.
SAE classification
The standard, created by the Society of Automotive Engineers, divides oils into categories depending on viscosity and temperature characteristics:
- winter, denoted by one or two numbers and the letter W (view ** W);
- summer, indicated by two digits;
- all-season, designated by a double number (type **W-**).
Table of correspondence between air temperatures and engine oil class.
API classification
The API standard consists of two Latin letters. Depending on the combination of letters, the oil is applicable to engines developed before a certain date. The classification depends on the type of ignition, as well as the operating conditions of the car. The quality of the oil is on the rise, depending on the second letter in the designation.
According to the standard, oils are divided into two categories according to their purpose:
- oil with the symbol S (from Service) for 4-stroke engines with spark ignition;
- oil with the letter C (for Commercial), designed for diesel engines (including agricultural machinery).
Table for decoding designations.
| Index | Note |
| SA | Not used |
| SB | Engines developed in 1930-1964, which are used on old-timers |
| SC | Motors up to 1964 |
| SD | Units created in the period from 1964 to 1968 |
| SE | Motors 1979-1972 |
| SF | For units put into production in 1973-1988 |
| SG | Motors of the 1989-1994 model, operated in severe conditions |
| SH | Similarly for engines 1995-1996 |
| SJ | Engines developed in 1997-2000 with increased fuel efficiency |
| SL | Motors of 2001-2003 with an extended service interval (improvement in washing and antioxidant characteristics) |
| SL+ | Enhanced oxidizability characteristics |
| SM | Engines, developments after 2004 |
| SN | Modern engines, developments after 2010. The oil provides an extended drain interval, reduces fuel consumption, allows the engine to run on biofuel |
For oil intended for filling in diesel engines, 14 classes are used. The fluid differs in the operating cycle of the motor - there are separate lubricants for a 2-stroke or 4-stroke engine. The cycle rate of the unit is reflected by a number added after the class designation.
Table for deciphering the designations of oils for diesel engines.
| Index | Note |
| CA | Early 1940 model diesels |
| CB | Motors built after 1949 |
| CC | For engines manufactured after 1961 |
| CD | Motors after 1965. In 1972, the standard for 2-stroke engines appeared |
| CE | Model 1983 motors |
| CF | Engines since 1994, while for 2-stroke engines the standard has been adopted since 1990 |
| CG | Adopted at the same time as CF |
| CH | Since 1998 |
| CI | Engines developed after 2004. Units with gas recirculation, the fuel must not contain more than 0.5% sulfur |
| CJ | Modern supercharged diesel engines built after 2010. The fuel must not contain more than 0.05% sulfur, the oil is suitable for the urea injection system |
According to the API classification, it is possible to create engine oils suitable for filling in diesel and gasoline engines. First, the type of unit for which the oil was developed is written, and then for which engine it is allowed to use. An example designation is API SL/CF.
ACEA classification
The ACEA International Class was created by the Association of European Manufacturers in 1995. The standard is constantly being developed, the latest release divides motor oils into three categories and 12 classes. When designating a grease according to ACEA, the year the standard was introduced and the release number (if it has changed since the first adoption) are indicated.
Oil types according to ACEA:
- category A / B, intended for use in gasoline or diesel engines installed in cars or minibuses;
- class C, specially designed for engines with exhaust gas afterburning systems (catalysts);
- category E for oil used in heavily loaded diesel engines of commercial vehicles.
General description of classes of category A / B.
General description of category C classes.
Engine oil of classes E4 and E6, as well as E7 and E9, is designed to work in diesel engines of trucks that comply with toxicity standards up to Euro-5. It is possible to use grease on units with a gas recirculation system, as well as particulate filters and SCR type catalytic converters.
When using motor oils of the ACEA standard, it is necessary to follow the operating instructions for the car.
Engine oil standards according to GOST
The state standard GOST 17479-1-85 adopted in 1985 provides for the division of oils into two groups:
- classes that differ in kinematic viscosity;
- groups that have differences in performance.
Depending on the viscosity, motor oils are divided into categories:
- summer, having indices in the range of 6-24;
- winter, with indices 2-6;
- all-weather, indicated by a double winter / summer index (for example, 3/8).
The standard specifies viscosity under the following conditions:
- at a temperature of 100 ºС;
- at a temperature of -18 ºС.
Application groups are designated by letters, with classes B-E divided into two sub-categories (gasoline or diesel).
| Group | The main characteristics of an engine designed for the use of oil |
| A | Unforced spark-ignition and compression-ignition powertrains |
| B1 | Gasoline engines with a low degree of boost, used in conditions that cause corrosion of plain bearings and form deposits |
| B2 | Small boost motors with compression ignition |
| IN 1 | Medium boost gasoline units used in conditions that lead to rapid oil oxidation and deposit formation |
| AT 2 | Medium boosted diesel engines requiring oil to reduce corrosion and wear |
| G1 | Motors with spark ignition, high degree of forcing. Operated in conditions that promote oil breakdown and deposit formation, as well as corrosion |
| G2 | High boost naturally aspirated and supercharged diesel engines used in conditions that promote the formation of deposits |
| D1 | For gasoline engines operating in more severe conditions than G1 |
| D 2 | Supercharged compression-ignition engines operating on fuels that place higher demands on oil |
| E1 | For very severe operating conditions of highly accelerated gasoline engines |
| E2 | Similarly for diesel engines (turbo and atmospheric) |
ISLAC Engine Oil Standards
The ILSAC standard is a relatively recent development thanks to the joint work of the US and Japanese Automobile Manufacturers' Associations (AAMA and JAMA, respectively). The classification aims to tighten the requirements for manufacturers of lubricating fluids.
In fact, ILSAC is a special case of the API standard, which is separated into a separate independent category. There are several ILSAC grades that correspond to the API classification.
Characteristics of the standard.
The ILSAC designation is applied on a label affixed to the engine oil canister in conjunction with API and SAE requirements.
The main properties of the oil, which are subject to the requirements of ILSAC:
- viscosity, the standard requires a reduction in value, which allows the use of oil in highly accelerated engines;
- oil film stability at high pressure (combined with low viscosity);
- reduction of energy costs for friction, which has a positive effect on fuel consumption;
- reduction of phosphorus to increase the life of catalytic converters;
- increased fluidity at low temperature, which provides improved filtration;
- reduction in oil consumption for waste (on serviceable engines) and evaporation;
- resistance to foaming during engine operation.
An example of ILSAC marking on a canister DEXOS Engine Oil Standards
The standard was developed by General Motors Corporation and consists of two stages:
- Dexos1 for Otto cycle engines (gasoline);
- Dexos2 for diesel engines.
The standard has been introduced since 2007. Factory fill oils are grade 5W-30. The use of synthetic or semi-synthetic lubricants is allowed.
Characteristics chart for ILSAC and Dexos1 oils The most common mistakes when choosing engine oil
Some of the most common mistakes car owners make when buying oil:
- The use of oil with a viscosity that does not meet the recommendations of the vehicle manufacturer. Exceeding the indicator leads to wear of parts during engine start-up and warm-up. Low viscosity does not provide normal operating conditions on a warm engine.
- The use of oil in winter, intended for the warm season. The error is rare, since modern fluids are suitable for use at any time of the year.
- Use of oil with a viscosity that does not match the air temperature. Automakers advise using a different fluid depending on the average temperature. Recommendations are available in the vehicle maintenance instructions.
- The use of oil that does not match the type of engine. Motor lubricants can be universal, as well as suitable only for gasoline or diesel engines. If the unit is equipped with a turbocharger, then the oil must have the appropriate approval. The use of a fluid that is not designed for use in turbocharged engines will damage the compressor bearings. If the unit is operated on gas fuel, then the appropriate oil must be used.
- Use of oil that does not correspond to the change intervals. Because of this, wear of parts occurs, coking of the internal parts of the engine with an aged substance.
- Use of counterfeit liquid. It is recommended to purchase oil at official points of sale. This is due to the fact that there are a significant number of fakes on the lubricants market. The use of counterfeit fluid will result in serious engine damage and overhaul.
What affects the wrong choice of engine oil?
The wrong choice of oil can cause:
- reducing the power of the car engine;
- increase in fuel consumption;
- difficult start of the unit at low air temperature;
- increased wear of engine parts, since oil that does not meet the requirements does not create a stable protective film on parts.
Photo gallery
The photo shows examples of motor oils of different types.
Video "Classification of oils according to SAE and API standards"
The video provided by the Lty D channel is devoted to the intricacies of classifying oils according to SAE and API standards.
Based on the requirements of a car engine, engine oil is selected according to two main criteria: API performance level and SAE viscosity.
Which one is better to use?
Motor manufacturers at the design stage are determined with brands of oils depending on operating conditions and design features. After that, life tests of engines are carried out and recommendations for use are issued. So, before choosing, you need to look into the instruction manual, what exactly is needed. The oil indicated in the instructions is the correct choice.If you do not want to fill in the original branded oil, then you can get by with non-original ones. And in order not to lose the warranty, you should choose it with the approval and approval of the auto concern. The approval of the auto manufacturer is one of the main guidelines when choosing. The designation of approval indicates not only the name of the brand of the car, but also a special index, which is comparable to what appears in the automotive documentation.
Russian legislation does not restrict the right of a car owner to use technical fluids of any brand. The main thing is that the product specifications comply with the manufacturer's recommendations. In the event of a breakdown of the engine, which was filled with non-original, but meeting the basic requirements of the oil, the dealer can refuse warranty repairs only if the examination establishes that it was counterfeit.
Use the oil recommended by the manufacturer. If you choose on your own, then it is selected according to two main parameters: by group and quality class. It would also be helpful to know.
SAE classification
The main property of engine oil is viscosity and its dependence on temperature over a wide range. Here is the standard SAE classification: 10W-40. The first designation "10W" indicates the application temperature, and "40" the viscosity. We will talk about each parameter separately.The most noticeable numbers on the canister speak of the viscosity of the oil - this is the SAE classification. Two numbers separated by the letter W indicate that it is all-season. The first digits indicate the minimum negative temperature at which the engine can be cranked. For example, when designating 0W-40, the lower temperature threshold is -35 ° C, and for 15W-40 it is -20 ° C. The number after the hyphen indicates the permissible range of viscosity changes at 100 ° C.
Operating ranges of winter, summer and all-weather oils
With an average climate, it is recommended to use the "universal" 10W - it will fit most cars. If the winters are severe, then oil of a class of at least 5W should be filled in (best would be - 0W). For summer operation, 10W is suitable.
- with vehicle mileage less than 50% from the planned resource (new engine), oils of classes 5W30 or 0W20 must be used. This is due to the fact that new engines have no wear, all clearances are minimal, so the bearings work at a lower viscosity.
- with a car mileage of more than 50% from the planned resource (technically serviceable engine), it is advisable to use oils of class 5W40. This is due to the fact that at high wear, the bearing capacity is compensated by an increase in viscosity.
Modern motors require low viscosity oil, because. it has low energy saving properties and saves fuel. Liquids with a viscosity of not more than 30 are poured from conveyors. If the mileage of the machine is high and increased consumption is noticeable, then oil with a higher viscosity index should be filled in.
API classification
The classification of oils according to the conditions of their use and the levels of performance properties has been repeatedly supplemented, but the principle of division into two categories - "S" and "C" has been preserved. Category "S" (Service) includes oils for gasoline engines, category "C" (Commercial) - designed for diesel engines.
API performance levels are subdivided into "S" categories in ascending order of quality into classes (SA, SB, SC, SD, SE, SF, SG, SH, SJ, SL, SM and SN). The further the second letter is from the beginning of the alphabet, the better. For gasoline engines, the most modern is the SN marking, and for diesel engines - CF. To designate universal oils that are used for gasoline engines and diesel engines, a double marking has been adopted, for example, SN / CF.
All fluids with a quality higher than SL can be classified as energy-saving - they save fuel. The difference in real operation will be 2-3%. You hardly feel it.
The oil of the latest API classification should be selected. The packaging must have a marking designation not lower than class SM or SN. It is this class that gives the best engine performance and reduces waste consumption.
The next step is to choose a brand. There is a wide choice here: domestic oils are comparable to many foreign ones - after all, modern base oils and additive packages are used in their production. The main thing is not to run into a fake and buy in company stores. Or choose in cans that are difficult to counterfeit.
Knowing the classes and standards of motor oils, the driver will always choose the right working fluid for his car. Today, in the automotive market, companies offer a huge selection of motor oils. In order not to overpay and not buy useless goods for your car, you should figure out what the classification of motor oils is and what categories it is divided into. For each engine, lubricant is selected according to two main criteria:
SAE viscosity
according to API (USA) or ACEA (Europe) certification - performance level.
After reading this material, you will know what engine oil consists of, what additives are added to the lubricant and how to choose the right working fluid for your car according to the specification.
Engine Oil and Additives - Definitions and Types
Any modern oil includes additives and an oil base (base). An oil containing a base on chemical synthesis is called synthetic. The mineral liquid has an oil base. Mixing synthetic and mineral bases in different proportions leads to the creation of their symbiosis - a semi-synthetic working fluid.
The base initially has operational and lubricating characteristics, but a modern engine will never work only on their basis. To ensure the desired properties, additives are added to motor oils, which take into account the life of the unit and different operating modes.
Additives
The main task of additives is to change the synthetic or mineral base of the lubricant and add useful characteristics. Several decades ago, working fluids were produced without additives, since the engines of that time did not require them. The need arose with the improvement of power plants, which began to differ from each other and produce much more power. The creation of a working fluid was influenced by the type of fuel, the number of cylinders, power characteristics, etc. After all, it is obvious that there should be different lubricants for Zhiguli and Porsche. Their difference can be seen in cost and quality.
To date, there is a huge number of additives, the following are the most common types:
- antioxidant
- thickening
- antiwear
- detergents
- anti-corrosion
- depressant
- dispersing
This is not a complete list, but standards require the use of these additives in almost any engine. For example, during the operation of a diesel unit, a large amount of carbon deposits appear, so the working fluid must have increased dispersing and washing properties. If we talk about turbocharged engines, then it should be flushed with lubricants with increased oxidation resistance and temperature resistance.
Before releasing a car for sale, each manufacturer calculates and checks which oil is suitable for the engine. This information is present in the car passport, therefore. It is also worth familiarizing yourself with the data on service intervals.
Sometimes we have to use working fluids from different companies. For example, you can take an emergency situation when there is no suitable oil with you, and the indication indicates that the lubricant level has dropped. After mixing, the motor must be thoroughly washed with special oil, which is called flushing oil. The unit should work on it for several minutes to remove excess additives and residues of oil bases.
If this is not done, then the active substances can harm the operation of the entire power plant and even disable it. Their combination can lead to increased viscosity, deposits or foaming. All these processes negatively affect the operation of the motor.
API - categories, symbols, tables
The API motor oil classification is the most commonly used today. It is named after the American Petroleum Institute (API), which developed the specification system. With its help, you can choose the type of lubricant, taking into account the type of motor and its age. The API specification is also known as the quality classification. API got this name due to the fact that modern motors are becoming lighter, more powerful and demanding. Oil manufacturers must develop new additives.
Over the years of the API's existence, the classification has been supplemented many times due to an increase in performance and conditions of use. But the principle has remained the same - and today working fluids are divided into two categories:
"S" - this category (Service) includes lubricants for 4-stroke gasoline units;
“C” - oil with this designation is bought by owners of cars with a diesel unit, so the class is suitable for agricultural machinery.
Depending on the performance, the creators of the specification decided to divide the category of gasoline engines into nine classes, and the diesel “C” into ten. Oils for diesel engines are also marked with a number that indicates which type of diesel the lubricant belongs to - 4-stroke or 2-stroke.
This table will provide an easier perception:
When buying oil, it is recommended to pay attention to the latest class from this specification. For a passenger car, fluids of at least SN or SM class are suitable. SM and SN are indicated in almost all operating books, since these classes reduce lubricant consumption for waste and give improved motor performance.
There are also universal oils that are designed for pouring into both diesel and gasoline power plants. These species have been double-labeled. For example, you can take SJ / SF, SF / CC, SG / CD and others.
Classification of motor oils according to ASEA
In addition to the American API specification, there is a European marking of motor oils called ACEA - the Association of European Automobile Manufacturers. These standards were adopted in place of the CCMS specification that was used on their cars until 1995. The requirements of the ACEA specification are similar to those of the API. It is useful for the motorist to know both options. VW, MAN, Fiat, BMW, DAF, Rolls-Royce, Porsche, Volvo are some of the companies that make up ACEA.
The European ACEA includes three classes of automotive motor oils - A, B, E. For each class, there are several categories, which are indicated by Arabic numerals. The next figure will be the year the class was put into operation. Sometimes the manufacturer writes the latest edition of these standards. So, the classes of modern motor oils:
A - gasoline engines (A1, A2, A3 and A5);
B - diesel units for trucks and cars of low power (B1, B2, B3, B4 and B5);
E - diesel engines for vehicles with high power (E1, E2, E3, E4, E5 and E7).
As you can see, ACEA motor oil classes also contain numbers that indicate the level of requirements. The higher the number, the greater the requirement for lubrication. Only A1 and B1 are an exception to the rule - they were decided to be classified as working fluids with a low viscosity index.
Viscosity classification
In addition to the API or ACEA specification, oils are also classified by viscosity - according to SAE. The main indicator of any SAE lubricant is viscosity, as well as its change at different temperatures (load in the power plant, cold start performance, operation in summer at high temperatures).
According to SAE viscosity, working fluids are divided as follows:
five summer viscosity grades (20, 30, 40, 50 and 60);
six winter categories (0W, 5W, 10W, 15W, 20W, 25W).
The larger the number in front of the letter W, the higher the viscosity index of a given working fluid. But most often you buy all-season motor oils, which can be immediately distinguished by a double SAE number - one shows the viscosity class during operation in the summer at elevated temperatures, and the second designation guarantees the preservation of viscosity during frost. 
Depending on the design, engine power, SAE temperature and viscosity ranges vary significantly, so this indicator must be taken seriously. The SAE designation is also the nodes that are involved in ensuring the proper operation of the power plant. Your vehicle's owner's manual will tell you which SAE oils are suitable for your engine.
Choosing the right lubricant
We figured out the tolerances of automotive engine oils, but the selection of a suitable fluid also depends on the service life. This is also indicated in the notation of classifications. Below are our main recommendations:
if the mileage of the car has not yet reached 25% of the planned resource (installation of a new engine), then the best choice would be oils of classes 10W30, 5W30;
with a run of 25-75% of the planned resource, it is recommended to use 5W30 or more stable 10W30 lubricants in winter, SAE 15W40, 10W40 in summer, the ideal all-weather option is SAE 5W40.
if the mileage is more than 75%, then in winter you need to take SAE 10W40 and SAE 5W40, in summer 15W40 or 20W40 will do, if all-weather lubricants are preferred, you should buy SAE 5W40.
Summing up
As you can see, there are a lot of aspects to the tolerances of automotive motor oils. But now you understand what the marking of engine oils for diesel and gasoline power units means. This knowledge will undoubtedly be useful to you, because when you come to any car store, you will see a huge amount of motor oils. Now you can understand their designation, distinguish them by viscosity, allowable temperature, mileage, etc.
Many motorists do not want to delve into tables and definitions, because you can always come to an official car service and get original engine oil there. There is no doubt about the quality of motor oils from the manufacturer, but not all drivers know that such fluids are more suitable for new cars.
Currently, the generally recognized international system for classifying motor oils by viscosity is SAE J300, developed by the Society of Automotive Engineers of the United States (Society of Automotive Engineers). The viscosity of the oil according to this system is expressed in arbitrary units - degrees of viscosity. The larger the number included in the SAE class designation, the higher the viscosity of the oil.
The specification describes three ranges of oil viscosity: winter, summer and all-weather. But, before considering them, a little theory. The temperature range of engine oil is mainly determined by two of its characteristics: kinematic and dynamic viscosity. Kinematic viscosity is measured in a capillary viscometer and indicates how easily an oil flows at a given temperature under the force of gravity in a thin capillary tube. Dynamic viscosity is measured in more complex installations - rotational viscometers. It shows how much the viscosity of the oil changes when the speed of movement of the lubricated parts relative to each other changes. With an increase in the speed of the relative movement of the lubricated parts, the viscosity decreases, and with a decrease, it increases.
Row winter oils: SAE 0W, 5W, 10W, 15W, 20W, 25W - indicated by a number and the letter "W" (Winter-Winter). For winter classes, two maximum values of low-temperature dynamic viscosity and a lower limit of kinematic viscosity at 100°C are established.
Low temperatures include:
crankability- shows the dynamic viscosity of the engine oil and the temperature at which the oil remains thin enough to be able to start the engine.
Pumpability- this is the dynamic viscosity of the oil, at which the oil can be pumped through the lubrication system and the engine will not operate in dry friction mode. The pumpability temperature is lower than the cranking temperature by 5 degrees.
The high-temperature properties of winter oils are characterized by the minimum kinematic viscosity at 100 ° C - an indicator that determines the minimum viscosity of engine oil when the engine is warm.
Row summer oils: SAE 20, 30, 40, 50, 60 - indicated by a number without a letter designation. The main properties of the summer range of oils are determined by:
- minimum and maximum kinematic viscosities at 100 ° C - an indicator that determines the minimum and maximum viscosity of engine oil when the engine is warm.
- minimum viscosity at 150°С and shear rate 106 s-1. The shear rate gradient is the ratio of the speed of movement of one friction surface relative to another to the size of the gap between them filled with oil. As the shear rate gradient increases, the viscosity of the oil decreases, but it increases again when the shear rate decreases.
Row multigrade oils: SAE 0W-20, 0W-30, 0W-40, 0W-50, 0W-60, 5W-20, 5W-30, 5W-40, 5W-50, 5W-60, 10W-20, 10W-30, 10W-40, 10W-50, 10W-60, 15W-30, 15W-40, 15W-50, 15W-60, 20W-30, 20W-40, 20W-50, 20W-60. The designation consists of a combination of the winter and summer rows separated by a dash. All-season oils must meet the criteria for both winter and summer oils at the same time. The smaller the number before the letter W, the lower the viscosity of the oil at low temperatures, the easier it is to start the engine cold with a starter and the better the pumpability of the oil through the lubrication system. The larger the number after the letter W, the greater the viscosity of the oil at high temperatures and the more reliable engine lubrication in hot weather.
Thus, the SAE class informs the consumer of the ambient temperature range in which the oil will provide:
- cranking the engine with a starter (for winter and multigrade oils)
- pumping oil with an oil pump through the engine lubrication system under pressure during cold start in a mode that does not allow dry friction in friction units (for winter and all-weather oils)
- reliable lubrication in summer during long-term operation at maximum speed and load conditions (for summer and all-weather oils)
Classification of engine oils by purpose and API performance levels
The most well-known international classification of motor oils by application and performance level is the API (American Petroleum Institute) classification.
The API classification divides motor oils into three categories:
- S (Service)- for gasoline engines of passenger cars, minibuses and light trucks.
- C (Commercial)- for diesel engines of commercial vehicles (trucks), industrial and agricultural tractors, road construction equipment.
- F- for use in high-speed diesel engines of heavy vehicles and heavy equipment that meet the 2017 emission standards.
The oil class designation consists of two letters of the Latin alphabet: the first (S, C or F) indicates the oil category, the second - the level of performance. The farther from the beginning of the alphabet the second letter, the higher the level of properties (i.e. the quality of the oil). Classes of diesel oils are additionally subdivided for two-stroke (CD-2, CF-2) and four-stroke diesel engines (CF-4, CG-4, CH-4). Most foreign motor oils are universal - they are used in both gasoline and diesel engines. Such oils have a dual designation, for example: SF / CC, CD / SF, etc. The main purpose of the oil is indicated by the first letters, i.e. SF / CC - "more gasoline", CD / SF - "more diesel". Energy-saving oils for gasoline engines are additionally indicated by the abbreviation EU (Energy Conservation).
To date, the API classification contains 4 active classes of category "S", 4 active classes of category "C" and 1 active class of category "F". But many manufacturers continue to produce oils of grades excluded from the specification, as cars with older engines continue to be used, which means that there is a need for these oils. The API recommends that any superior incumbent "S" class replaces the inferior incumbent class. For diesel oils, the higher operating class usually, but not always, supersedes the lower class.
API Specification for Gasoline Engines
| Class | Status | Purpose |
| SN | current | Introduced in October 2010. Provides improved piston protection against high temperature deposits, increased contamination control and seal compatibility. API SN with Resource Conserving complies with ILSAC GF-5, combining performance with improved fuel economy, turbocharger protection, compatibility with emission control systems and protection for engines running on ethanol fuels up to E85. |
| SM | current | For engines 2010 and older model years |
| SL | current | For engines 2004 and older model years |
| SJ | current | For engines 2001 and older model years |
| SH | Outdated | For 1996 and older engines |
| SG | Outdated | For 1993 and older engines |
| SF | Outdated | For 1988 and older engines |
| SE | Outdated | Not suitable for use in engines manufactured after 1979. |
| SD | Outdated | Not suitable for use in engines manufactured after 1971. Use in more modern motors may result in unsatisfactory performance or breakdowns. |
| SC | Outdated | Not suitable for use in engines manufactured after 1967. Use in more modern motors may result in unsatisfactory performance or breakdowns. |
| SB | Outdated | Not suitable for use in engines manufactured after 1951. Use in more modern motors may result in unsatisfactory performance or breakdowns. |
| SA | Outdated | Does not contain additives. Not suitable for use in engines manufactured after 1930. Use in more modern motors may result in unsatisfactory performance or breakdowns. |
API specification for diesel engines
| Class | Status | Purpose |
| CK-4 | current | Designed for high speed 4-stroke diesel engines that meet 2017 model year on-highway and Tier 4 off-road emission standards, as well as previous model year engines. These oils are formulated for use with fuels containing up to 500 ppm sulfur (0.05% by weight). However, the use of these oils with fuels containing more than 15 ppm sulfur (0.0015% by weight) may affect the life of the aftertreatment system and/or the oil change interval. These oils are especially effective in improving the durability of exhaust systems that use diesel particulate filters and other high-tech components. API CK-4 have improved oxidation protection, do not lose viscosity as a result of shear and aeration loads, and also do not spoil the catalyst and diesel particulate filter, reduce engine wear, piston deposits, are slightly susceptible to loss of low and high temperature properties and increase in viscosity due to - for soot pollution. API CK-4 oils outperform CJ-4, CI-4, CI-4 PLUS, CI-4, CH-4 and can effectively lubricate engines designed for these categories. When using CK-4 oils with fuel containing more than 15 ppm sulfur, the engine manufacturer's recommendations for service intervals must be followed. |
| CJ-4 | current | Introduced in 2006. For high-speed, four-stroke engines meeting emission standards introduced in 2007. Oils of this class are designed to operate on fuel containing no more than 0.05% sulfur. However, in order to meet emission standards, ensure reliable operation of exhaust gas treatment systems and achieve extended oil change intervals, it is necessary to use diesel fuel with a sulfur content not exceeding 0.0015%. CJ-4 class engine oils have been developed for engines equipped with the most advanced emission reduction systems (particulate filters, exhaust gas recirculation systems, etc.). CJ-4 class oils have improved protective properties, increased oxidative, low and high temperature stability, extended replacement intervals. However, when using fuel with a sulfur content of more than 0.0015%, the change intervals must be reduced. CJ-4 grade oils can replace CI-4, CH-4, CG-4 and CF-4 oils. |
| CI-4 | current | Introduced in 2002. For high-speed, four-stroke engines meeting emission standards introduced in 2004. Oils of this class are designed for engines with an exhaust gas recirculation (EGR) system and running on diesel fuel with a sulfur content of up to 0.5%. Can replace oils of classes CD, CE, CF-4, CG-4 and CH-4. |
| CH-4 | current | Introduced in 1998. For high speed 4-stroke engines meeting 1998 emission standards. Designed for operation using fuel with sulfur content up to 0.5%. Can be used in place of CD, CE, CF-4 and CG-4 oils. |
| CG-4 | Outdated (until 31.08.09) | Introduced in 1995. For heavy-duty, high-speed, four-stroke engines running on fuels with a sulfur content of less than 0.5%. It is used in engines that meet the requirements of the 1994 emission standard. Can replace oils of classes CD, CE, CF-4. |
| CF-4 | Outdated | Introduced in 1990. For high-speed, four-stroke, naturally aspirated and supercharged engines. Can be used in place of CD and CE oils. |
| CF-2 | Outdated | Introduced in 1994. For heavily loaded two-stroke diesel engines. Can be used in place of CD-II class oils. |
| CF | Outdated | Introduced in 1994. For SUVs, vortex-chamber and pre-chamber diesel engines, as well as diesel engines running on fuel with a high sulfur content (up to 0.5%). Can be used in place of CD class oils. |
| CE | Outdated | Introduced in 1985. For high-speed, four-stroke, naturally aspirated and supercharged engines. Can be used in place of CC and CD oils. |
| CD-II | Outdated | Introduced in 1985. For two stroke engines. |
| CD | Outdated | Introduced in 1955. For some naturally aspirated and turbocharged engines. |
| CC | Outdated | Not suitable for use in diesel engines manufactured after 1990. |
| CB | Outdated | Not suitable for use in diesel engines manufactured after 1961. |
| CA | Outdated | Not suitable for use in diesel engines manufactured after 1959. |
| Class | Status | Purpose |
| FA-4 | current | The FA-4 category describes certain XW-30 oils specifically designed for use in certain high-speed four-stroke diesel engines that meet the 2017 highway greenhouse gas emission regulations. These oils are designed for use with fuels containing up to 15 ppm sulfur (0.0015% by weight). Follow manufacturer's recommendations for compatibility with FA-4 oils. These oils have a high temperature viscosity range when operating at high shear rates of 2.9cP–3.2cP, which helps reduce greenhouse gas emissions. These oils are especially effective in improving the durability of exhaust systems that use diesel particulate filters and other high-tech components. API CK-4 have improved oxidation protection, do not lose viscosity as a result of shear and aeration loads, and also do not spoil the catalyst and diesel particulate filter, reduce engine wear, piston deposits, are slightly susceptible to loss of low and high temperature properties and increase in viscosity due to - for soot pollution. API FA-4 oils are not interchangeable or backward compatible with API CK-4, CJ-4, CI-4, CI-4 PLUS, CI-4 and CH-4. Refer to the engine manufacturer's recommendations to determine if API FA-4 oils are suitable for use. API FA-4 oils are not recommended for use with fuels with a sulfur content greater than 15 ppm. For fuels with a sulfur content greater than 15 ppm, see the engine manufacturer's recommendations. |
Marking
The ILSAC classification was developed by the International Lubricant Approval and Standards Committee (ILSAC) in conjunction with JAMA (Japan Automobile Manufacturers Association) and AAMA (Automotive Manufacturers Association of America). For gasoline engines of Japanese-made passenger cars, this classification is best suited; for American cars, both ILSAC and API oils are equivalent. The current ILSAC standard, adopted in 2010, is GF-5. Oils in this grade provide improved protection of pistons and turbochargers from high temperature deposits, reduced pollution, improved fuel economy and compatibility with aftertreatment systems and seals, as well as engine protection when using ethanol-containing fuels up to E85.
Classification of motor oils by purpose and ACEA performance levels
The Association of European Automobile Manufacturers (Association des Constracteuis Europeen des Automobiles) - on January 1, 1996, introduced its own classification of motor oils, which has been updated several times since then. Here is the classification introduced since December 22, 2008.
The requirements of European standards for the quality of motor oils are more stringent than American ones, because. in Europe, operating conditions and engine design differ from those in the US:
- a higher degree of forcing and maximum speed;
- less weight of engines;
- greater specific power;
- high permissible speeds of movement;
- heavier urban regimes.
In view of these features, motor oil tests are carried out on European engines and according to methods that differ from American ones. This does not allow for a direct comparison of ACEA and API levels of requirements and standards.
The ACEA classification divides motor oils into 3 classes:
- A/B- for gasoline engines and diesel engines of cars and light trucks;
- C- compatible with exhaust gas neutralizers;
- E- for powerful diesel trucks.
A/B- oils for gasoline and diesel engines
A3/B3 Designed for high performance gasoline and light diesel engines designed for use and/or extended oil change intervals as recommended by engine manufacturers and/or for heavy duty and/or multigrade use of low viscosity oils.
A3/B4 Designed for use in high-performance gasoline engines and diesel engines with direct fuel injection. Can be used in place of A3/B3 class oils.
A5/B5 Designed for high performance gasoline engines and light diesel engines that are designed to use oils with extended drain intervals that provide low coefficient of friction, low viscosity at high temperature and high shear rate (2.9 to 3.5 mPa.s.) These oils may not be suitable for work in some engines. You must follow the owner's manual for the vehicle.
C- oils compatible with catalytic converters
C1 Designed for vehicles equipped with particulate filters and three-way catalytic converters. They are used in high performance gasoline engines and passenger diesel engines requiring oils that provide low friction, low viscosity, low sulfate ash content, low sulfur and phosphorus content, having a minimum viscosity at high temperatures and high shear rates of 2.9 mPa.s. These oils extend the life of diesel particulate filters and catalytic converters and contribute to fuel economy. May not be suitable for use in some engines. You must follow the owner's manual for the vehicle.
C2 Designed for vehicles equipped with particulate filters and three-way catalytic converters. They are used in high performance gasoline engines and light diesel engines designed to use low friction, low viscosity oils that have a minimum viscosity at high temperatures and high shear rates of 2.9 mPa.s. These oils extend the life of diesel particulate filters and catalytic converters and contribute to fuel economy. May not be suitable for use in some engines. You must follow the owner's manual for the vehicle.
C3 Designed for vehicles equipped with particulate filters and three-way catalytic converters. They are used in high-performance gasoline engines and passenger diesel engines having a minimum viscosity at high temperatures and high shear rates of 3.5 mPa.s. These oils extend the life of particulate filters and catalytic converters. May not be suitable for use in some engines. You must follow the owner's manual for the vehicle.
C4 Designed for vehicles equipped with particulate filters and three-way catalytic converters. They are used in high-performance gasoline engines and passenger diesel engines requiring oils with a low sulfate ash content, low sulfur and phosphorus content, having a minimum viscosity at high temperatures and high shear rates of 3.5mPa.s. These oils extend the life of particulate filters and catalytic converters. May not be suitable for use in some engines. You must follow the owner's manual for the vehicle.
C5 Designed for vehicles equipped with particulate filters and three-way catalytic converters. They are used in high-performance gasoline engines and passenger diesel engines requiring oils with a low sulfate ash content, low sulfur and phosphorus content, having a minimum viscosity at high temperatures and high shear rates of 2.6mPa.s. These oils extend the life of particulate filters and catalytic converters. May not be suitable for use in some engines. You must follow the owner's manual for the vehicle.
E- for powerful diesel trucks
E4 Oils that provide high piston cleanliness, wear protection, high resistance to soot contamination and stable properties throughout the entire period of operation. Recommended for modern diesel engines that meet the requirements of Euro 1, Euro 2, Euro 3, Euro 4 and Euro 5 and operate in very severe conditions with significantly extended drain intervals (in accordance with manufacturers' recommendations). They can only be used in engines without a diesel particulate filter, and in some engines with exhaust gas recirculation and nitrogen oxide emission reduction systems. However, manufacturers' recommendations may differ, so you must follow the vehicle's operating instructions.
E6 Oils that provide high piston cleanliness, wear protection, high resistance to soot contamination and stable properties throughout the entire period of operation. Recommended for modern diesel engines that meet the requirements of Euro 1, Euro 2, Euro 3, Euro 4 and Euro 5 and operate in very severe conditions with significantly extended drain intervals (in accordance with manufacturers' recommendations). Can be used in engines with an exhaust gas recirculation system, with or without a diesel particulate filter, and for engines with nitrogen oxide emission reduction systems. Oils of this class are strongly recommended for engines equipped with particulate filters and designed to operate on fuels with a low sulfur content. However, manufacturers' recommendations may differ, so you must follow the vehicle's operating instructions.
E7 Oils that effectively keep pistons clean and protect against varnish deposits. They provide excellent wear protection, high resistance to soot contamination and stable properties throughout the entire period of operation. Recommended for modern diesel engines that meet the requirements of Euro-1, Euro-2, Euro-3, Euro-4 and Euro-5 and operate in severe conditions with extended drain intervals (in accordance with manufacturers' recommendations). Recommended for use in engines without diesel particulate filters and for most engines equipped with exhaust gas recirculation and nitrogen oxide emission reduction systems. However, manufacturers' recommendations may differ, so you must follow the vehicle's operating instructions.
E9 Oils that effectively keep pistons clean and protect against varnish deposits. They provide excellent wear protection, high resistance to soot contamination and stable properties throughout the entire period of operation. Recommended for modern diesel engines that meet the requirements of Euro-1, Euro-2, Euro-3, Euro-4 and Euro-5 and operate in severe conditions with extended drain intervals (in accordance with manufacturers' recommendations). They can be used in engines with or without particulate filters and in most engines equipped with exhaust gas recirculation and nitrogen oxide emission reduction systems. Oils of this class are strongly recommended for engines equipped with particulate filters and designed to operate on fuels with a low sulfur content. However, manufacturers' recommendations may differ, so you must follow the vehicle's operating instructions.
Classification of motor oils by viscosity, purpose and levels of performance properties GOST
| Viscosity groups of motor oils and their approximate compliance with the SAE classification | |||||
| GOST | SAE | GOST | SAE | GOST | SAE |
| 3h | 5W | 6 | 20 | 3z/8 | 5W-20 |
| 4h | 10W | 8 | 20 | 4z/6 | 10W-20 |
| 5z | 15W | 10 | 30 | 4z/8 | 10W-20 |
| 6z | 20W | 12 | 30 | 4g/10 | 10W-30 |
| 14 | 40 | 5g/10 | 15W-30 | ||
| 16 | 40 | 5z/12 | 15W-30 | ||
| 20 | 50 | 5z/14 | 15W-40 | ||
| 24 | 60 | 6z/10 | 20W-30 | ||
| 6z/14 | 20W-40 | ||||
| 6z/16 | 20W-40 | ||||
| Groups of motor oils by purpose and performance properties and their approximate compliance with the API classification | |||
| GOST | API | Recommended area of application | |
| A | SB | Unforced gasoline engines and diesel engines | |
| B | B1 | SC | Lightly boosted gasoline engines operating in conditions that promote high temperature deposits and bearing corrosion |
| B2 | CA | Low boosted diesels | |
| IN | IN 1 | SD | Medium-boosted gasoline engines operating in conditions that promote oil oxidation and the formation of deposits of all kinds |
| AT 2 | CB | Medium-forced diesel engines that place high demands on the anti-corrosion, anti-wear properties of oils and the ability to prevent the formation of high-temperature deposits | |
| G | G1 | SE | Highly accelerated gasoline engines operating under severe operating conditions that contribute to oil oxidation, the formation of deposits of all kinds and corrosion |
| G2 | CC | Highly boosted naturally aspirated or moderately aspirated diesel engines operating under operating conditions conducive to the formation of high temperature deposits | |
| D | D1 | SF | Highly accelerated gasoline engines operating in operating conditions that are more severe than for group G oils |
| D 2 | CD | Highly accelerated supercharged diesel engines operating in severe operating conditions or when the fuel used requires the use of oils with high neutralizing ability, anti-corrosion and anti-wear properties, low tendency to form all types of deposits | |
| E | E1 | SG | Highly accelerated gasoline engines and diesel engines operating under operating conditions more severe than for oils of groups D1 and D2 |
| E2 | CF-4 | They are distinguished by increased dispersing ability, better anti-wear properties | |
According to GOST 17479.1-85, the marking of oils includes the following characters:
- the letter M (motor)
- one or two numbers separated by a fraction indicating the viscosity grade or grades (for multigrade oils). For all-weather oils, the figure in the numerator characterizes the winter class, and in the denominator - the summer one; the letter "z" indicates that the oil is thickened, i.e. contains a thickening (viscosity) additive.
- one or two letters (from A to E) indicating the level of performance and scope of this oil. Universal oils are designated by a letter without an index or by two different letters with different indexes. Index 1 - assigned to oils for gasoline engines, index 2 - to diesel oils.
For example, the M-6z / 10V brand indicates that this is an all-weather motor oil, universal for medium-powered diesels and gasoline engines (group B). M-4z / 8-V2G1 - all-weather motor oil, universal for medium-powered diesel engines (B2 group) and high-powered gasoline engines (G1 group).
Vehicle manufacturer specifications
The API and ACEA classifications set out minimum basic requirements that are agreed upon between oil and oil additive manufacturers and vehicle manufacturers. The latter have the right to put forward their own additional requirements for oils, which are formulated in the specifications of car factories. Since the designs of engines of different brands differ from each other, the operating conditions of the oil in them are not quite the same. Therefore, car manufacturers conduct oil tests on engines of their own production. Based on this, either a certain class is indicated according to some generally accepted classification, or they make up their own specifications, which indicate specific brands of oils approved for use. The manufacturer's specifications are always present in the car's operating instructions, and their number is applied to the oil packaging next to the designation of its performance class.
