QUALITY Engine oils are also classified in terms of quality. The American API standard or the European ACEA standard are most often used (European Association of Engine Manufacturers – THAT, previously CCMC). The basis for the emergence of these two separate divisions was the differences in unit construction and operating conditions between the US and Europe. Each of them divides oils into two main groups: for gasoline and diesel engines. The quality classification determines the performance of the oil and its suitability for lubrication of a certain group of motors. To fully evaluate them, laboratory tests are not enough. The classification is based primarily on long-term engine tests both on the dynamometer, as well as in road tests.
API standards as the most universal and easily understandable are most often used. The letter S denotes oils for gasoline engines, and C for diesel. They are followed by a second letter – the further in the alphabet, the oil is of higher quality, more precisely, complies with newer standards and can be used to lubricate newly constructed units. Currently, the most advanced oils are in the grades SM and CI-4. If the product has a combined mark, e.g.. SL/CF, means, that it meets the requirements of the standard for gasoline and diesel engines, except that the priority in the application is determined by this, which letter – S or C – appears first. The oil quality requirements are specified by the engine or car manufacturer. It is, of course, possible to use products of a higher quality than recommended, but – especially in older design power units – it is unlikely to bring any noticeable benefit.
Currently in force (from 2004 year) the ACEA classification introduces a division into oils intended for engines with catalytic converters (gasoline and light diesels) marked with the letter C., universal for gasoline and light diesel engines – litery A/B
– and heavy and highly loaded diesel engines – letter E. The symbols are supplemented with the figure following the letter – 1, 3,4 i 5 for category A / B, from 1 do 3 for category C., and 2, 4, 6, 7 for category E. Grade oils 1 they are supposed to contribute to the reduction
fuel consumption, 3 – are oils for heavy duty engines with extended drain intervals, 4 – are products for direct injection units, a 5 – combine the features of the earlier classes, they have more stringent testing procedures. To end 2006 Year, you can still find signs according to ACEA from before 2004 r., where there was no category C, categories A and B were used separately and there was a class 2 which is the standard level. In category E, classes from 2 do 5. Both classifications (i.e.. API and ACEA) are successively supplemented with higher oil grades.
The issue of classification is further complicated by this, that in addition to the aforementioned international standards, well-known manufacturers have developed their own research tests, the fulfillment of which determines the approval of the use of oil in their engines. Of the many specifications of power unit manufacturers, the most famous are: ISLE OF MAN, VOLVO, Volkswagen and Mercedes-Benz, as well as Porsche.
Products of the same classes, and different manufacturers, have very similar properties, therefore choosing a lubricant, more attention should be paid to markings than to its brand. It is also permissible to mix products from different manufacturers while maintaining the same viscosity and quality classes. If we follow the basic rules of operation – Above all, strictly observe the change dates and check the oil level regularly, we can be sure, that the drive unit will pay you back with a correspondingly longer service life.
