European oil manufacturers classify their products according to the ACEA system (Association dec Constructeurs Europeens d’Automobiles), which takes into account the features of European engine technology. Oils for gasoline engines, depending on the quality according to the ACEA classification, are divided into groups from A1-96 to A3-96; engine oils for diesel engines are divided into groups from B1-96 to B3-96. At the same time, the marking AZ and, accordingly, B3 indicates the oil of the highest quality.
The quality of the engine oil of American manufacturers is indicated by the API system (American Petroleum Institut). The characteristic of the oil is given, depending on the circumstances, in two letters. The first letter indicates the scope: S (Servicej oil is used in gasoline engines. WITH (Commercial) — oil is applied in diesel engines. The second letter indicates the quality in alphabetical order. According to the API specification, SJ oil for gasoline engines and CF oil for diesel engines are of the highest quality.
Caution: Engine oils that are designated by the manufacturer as oils for diesel engines only are not suitable for gasoline engines. However, there are oils that can be used in both gasoline and diesel engines. Both specifications are indicated on the packaging of such oils (e.g. ACEA AZ-96/VZ-96 or API SH/CD). BMW has set different standards for its engines and depot engine oils for long life oils (Longlife-Ole) and special oils (Spezialole).