UNDERSTANDING THE STANDARDS OF ENGINE OILS
Choosing the right engine oil for your vehicle requires careful consideration, from oil types to your engine specification – diesel or gasoline.
The right oil will save you from engine and performance problems. Let’s get you familiar with three different standards that are used in the current market to describe engine oils.
The ACEA Standard
ACEA stands for the European Automobile Manufactures’ Association. It is a quality indicator that uses numeric and letter combination, e.g. A1, with the letter indicating the type of engine that the oil is designed for. ACEA codes consist of the following:
A – oils designed for petrol engines.
B – oils designed for private car diesel engines.
C – oils for light engines equipped with catalytic converters or particulate filters.
E – oils for commercial vehicles and trucks.
As shown by the above example, the letter is followed by a number that indicates the specific performances the oil must provide. Greater numbers signal greater oil performance.
READ ALSO: DIESEL ENGINE MAINTENANCE GOES BEYOND ROUTINE OIL REPLACEMENT
There are three category combinations for petrol and diesel engines: A3/B3, A3/B4, A5/B5.
Oils for petrol and private car diesel engines (B1) that are designed to use low viscosity oils.
Oils for petrol and diesel (B3) engines. These oils have extended drain intervals as recommended by car manufacturers.
Similar to A3/B3, A3/B4 oils can be used for direct injection diesel engines in private cars.
A5/B5 oils have the same standard as A1/B1, but with longer replacement intervals.
Other than A and B combinations, there are also five combination categories for vehicles with a pollution control device (C1, C2, C3, C4, C5) and four categories for commercial vehicles and trucks (E4, E6, E7, E9). In the E category, two are for vehicles with a pollution control device, E6 and E9.
The SAE Standard
SAE, or the Society of Automotive Engineers, is the standard that describes the degree of oil viscosity. SAE is indicated on the front of an oil packaging and its multigrade system consists of digit-letter combinations, the 00W-00 index.
The digits indicate viscosity levels; the digits on the left of W represent viscosity level at lower temperatures, while the back digits describe viscosity level at higher temperatures. For the front digits, lower numbers indicate that the oil will still pump in a colder environment.
Some common SAE grades in the market are SAE 10W-30, 10W-40 or 20W-40, 20W-50. An engine oil graded SAW 10W-40, for example, shows a good range of viscosity level that allows the oil to perform equally well at both low and high temperatures.
The API Standard
The API, or the American Petroleum Institute, classifies oils based on several criteria: dispersive and detergent power, and protection against wear, oxidation, and corrosion.
API classifications consist of letter-letter combinations with the first letter denoting application. S, or spark ignition, denotes oils for petrol engines and C, or combustion, mean the oil is for diesel engines. For the second letter, the further it is in the alphabet, the higher the quality of oil. A couple of examples are SM or SJ, which will have a lower performance than an SN oil.
Oils that are designed for the latest vehicle models are usually already of high performance. Their second letter will be closer to Z. This is also why oils for earlier and later models will be different, as their engines have unique needs.