Every car owner should be able to decipher the marking of the engine oil, printed on the package of the product, because the key to a durable and stable engine operation is the use of quality engine oil, which characteristics meet all the requirements of the manufacturer. Such serious requirements are imposed by them due to the fact that oils have to work in a wide temperature range and under high pressure.
The engine oil marking contains all the necessary information for proper selection, you just need to know how to interpret it
In order to streamline and simplify the procedure of selecting oil for a particular type of engine according to the required characteristics and the tasks assigned to it, a number of international standards have been developed. The world oil manufacturers use these universally recognized classifications:
There are 2 main classes of engine oils, depending on the type of engine: gasoline or diesel, although there is also a universal oil. The designation data is always indicated on the label. Any engine oil consists of a base composition (mineral oil), which is its base, and certain additives. The base of the lubricating fluid is an oil fraction, which is obtained by refining oil or artificially. Therefore, according to the chemical composition are divided into:
On the canister, along with other markings, the chemical composition is always indicated.
What may be on the label of an oil canister:
- SAE viscosity grade.
- API and ACEA specifications.
- Automobile manufacturer’s approvals.
- Batch number and date of manufacture.
- Pseudo labeling (is not a recognized standard label, but is used as a marketing ploy, e.g. fully syntetic, HC, with the addition of smart molecules, etc.).
- Special categories of motor oils.
- To help you buy exactly the oil that will suit your car engine best, we will decipher the most important engine oil markings.
The most important characteristic that is indicated in the marking on the canister is the SAE viscosity index – an international standard that regulates the viscosity of oils at plus and minus temperatures (limit value).
According to the SAE standard oils are denoted in the format XW-Y, where X and Y are certain numbers. The first number is a reference to the minimum temperature at which the oil can normally be pumped through the ducts and the engine can be cranked without difficulty. The letter W stands for the English word Winter.
The second number conventionally means the minimum and maximum value of the high-temperature viscosity limit of the oil when heated to the operating temperature. The higher the value of the number, the thicker it is when heated, and vice versa.
Therefore, oils are necessarily divided into three types depending on the value of the viscosity:
- winter oils
- summer oils
- multigrade oils
When choosing an oil viscosity (of the ones approved for use in the engine of your car) you should be guided by the following rule: the more mileage/older the engine, the higher the high-temperature oil viscosity should be.
Viscosity characteristics, are the first and most important element of the classification and labeling of motor oils, but not the only one – it is not right to choose an oil solely by its viscosity. It is always necessary to choose the right ratio of oil properties to its operating conditions.
Each oil besides viscosity has a different set of operational properties (detergent, antioxidant, antiwear properties, propensity to various sediments, corrosive activity and others). They allow defining possible field of their application.
API marking of motor oils
The main indicators in API classification are engine type, engine operation mode, oil performance, application conditions and year of production. The standard divides oils into two categories:
- Category “S” – shows intended for gasoline engines;
- Category “C” – indicates intended for diesel vehicles.
How to decipher the API marking?
As we have already found out, the API marking can begin with the letter S or C, which will talk about the type of engine in which you can pour, and another letter of the oil class designation, which shows the level of operational properties.
According to this classification, the deciphering of the marking of engine oils is as follows:
- The abbreviation EC, which is immediately after the API, stands for energy-saving oils;
- The Roman numeral after this abbreviation indicates the fuel economy level;
- S (Service) denotes the use of oil for gasoline engines;
- C (Commercial) denotes oils for diesel engines;
- One of these letters is followed by the level of performance indicated by the letters from A (the lowest level) to N and beyond (the higher the alphabetical order of the second letter in the designation, the higher the oil grade);
- Multi-purpose oils have the letters of both categories in a slash line (e.g.: API SL/CF);
- API marking for diesel oil is divided into two-stroke (number 2 at the end) and four-stroke (number 4).
Those engine oils which have passed the API/SAE test and meet the requirements of the current quality categories are marked on the labels with a circular graphic symbol. At the top there is “API” (API Service), in the middle the SAE viscosity grade, as well as the possible energy saving grade.
ACEA classification of motor oils
The ACEA classification was developed by the Association of European Automobile Manufacturers. It specifies the performance, purpose and category of the engine oil. ACEA classes are also divided into diesel and gasoline.
The latest edition of the standard divides oils into 3 categories and 12 classes:
- A/B – gasoline and diesel engines for passenger cars, vans, vans (A1/B1-12, A3/B3-12, A3/B4-12, A5/B5-12);
- C – gasoline and diesel engines with catalytic converter (C1-12, C2-12, C3-12, C4-12);
- E – truck diesel engines (E4-12, E6-12, E7-12, E9-12).
ILSAC classification of motor oils
ILSAC – a joint invention of Japan and America, the International Committee for Standardization and Approval of Motor Oils has issued five standards for motor oils: ILSAC GF-1, ILSAC GF-2, ILSAC GF-3, ILSAC GF-4 and ILSAC GF-5. They are completely similar to the API grades, the only difference is that the oils corresponding to the ILSAC classification are energy-saving and multigrade. This classification is best suited for Japanese cars.
Conformity of ILSAC grades to API:
- GF-1 (obsolete) – meets the oil quality requirement similar to the API SH category; SAE 0W-XX, 5W-XX, 10W-XX viscosity, where XX-30, 40, 50,60.
- GF-2 – meets the oil quality requirements of API SJ, and viscosity requirements of SAE 0W-20, 5W-20.
- GF-3 – is analogue of API SL category and is introduced since 2001.
- ILSAC GF-4 and GF-5 are analogues of SM and SN respectively.
In addition, within the framework of ISLAC standard for Japanese cars with turbocharged diesel engines, JASO DX-1 class is used separately. This automotive oil grade provides for engines of modern cars with high environmental parameters and built-in turbines.