American Petroleum Institute classification (API — American Petroleum Institute) determines the performance properties of the oil. Motor oils in Ney are divided into classes, which are indicated in Latin letters. The first letter characterizes the purpose of engine oil: for a diesel or gasoline engine. Oil for a gasoline engine is designated by the letter S (Service), and diesel - C (Commercial). Oil for diesel engines, in turn, can be intended for two-stroke or four-stroke engines. The second letter in the class designation characterizes «quality» oils, that is, compliance with certain technical requirements. After the development and certification of a new class of engine oil with improved properties, it is assigned the next letter of the Latin alphabet. The closer to the end of the alphabet is the second letter in the group designation, the higher the requirements the oil will meet. The last certified class of motor oils for gasoline engines - SN - was adopted in 2010, for diesel engines - CJ-4 - was adopted in 2010. As new classes of oil appear, the old ones are gradually cancelled. Engine oils classified as SH/CE and «older», are out of production.
Universal motor oil, which can be used in both gasoline and diesel engines, has a double marking, indicating the oil quality group for each type of engine. The number 2 or 4 in the designation of the diesel oil group indicates the number of strokes in the engine for which this oil is intended. If the oil has energy-saving properties, in its designation after the group indication there will be additional letters FE or EC (Fuel Economy or Energy Conserving respectively). The letters may also be followed by a Roman numeral, which indicates the nominal amount of savings (II - energy savings up to 2.7%, without a figure - 1.7%).
The API classification of engine oil has become widespread.
European Automobile Manufacturers Association classification (ASEA - Association des Constructers Europeans des Automobiles) also determines the performance properties of engine oil.
Engine oils by appointment (for diesel or petrol engine) divided into groups, which are denoted by the Latin letters A, B, C and E. The letter A denotes oil for a gasoline engine, B for a diesel engine of a passenger car and E for a diesel engine of a truck. The letter C denotes oils for diesel and gasoline engines that meet Euro 4 standards. The number after the letter indicates the performance class that the oil meets. The larger the number, the higher the oil grade. Two more digits after the dash, present in the oil marking, indicate the year of adoption of the relevant operational requirements, which the oil complies with.
Classification of the International Committee for the Approval and Standardization of Lubricants (ILSAC — International Lubricant Standartization and Approval Committee). This standard was developed jointly by the Automobile Manufacturers Association of Japan and the Automobile Manufacturers Association of America. Currently, the standard provides for three classes of oils for gasoline engines, which are indicated by two letters GF and the numbers 1-5. The highest performance requirements are in the GF-5 class. All ILSAC certified motor oils are energy efficient.
Engine oil classifications exist according to other standards. So, automakers often develop additional requirements for engine oil and use their in-house oil class marking. Domestic oil manufacturers sometimes mark viscosity in accordance with GOST, but at the same time duplicate it with SAE marking.
The marking of the oil, indicating its properties, is applied to the packaging.
An example of labeling oil on a package: 1 - marking of oil compliance with the technical requirements of manufacturers; 2 - the name of the oil; 3 - oil viscosity marking
An example of marking the compliance of engine oil with the technical requirements of European manufacturers: 1 - according to ACEA standards, the oil corresponds to the quality class AZ / B4; 2 - according to API standards, the oil corresponds to the quality class SM / CF; 3 - marking of compliance with the requirements of the automaker
An example of marking the compliance of engine oil with the technical requirements of international standards: 1 - oil viscosity according to SAE 5W-30; 2 - according to API standards, the oil corresponds to the SM quality class; 3 - API and SAE engine oil certification mark (API -classification designation; SERVICE - oil for gasoline engines; SM oil class; SAE 5W-30 - viscosity grade; ENERGY CONSERVING II - oil has energy-saving properties; 4 - designation of compliance with API and ILSAC requirements; 5 - according to ILSAC standards, the oil complies with class GF-4