The current API Service Classification is SN
The labels include two important pieces of information to determine if an engine oil is appropriate for use in your vehicle. The first piece of information speaks to viscosity grade. The Society of Automotive Engineers (SAE) defines a numerical system for grading motor oils according to viscosity. The suffixes (0, 5, 10, 15 and 25) followed by the letter W designate the engine oil's "winter" grade.
Look to your owner's manual. It specifies the viscosity grade required for your car's engine. Today, the most common grades are 5W-30.
Watch for the "W"
Whereas the labeling on the bottle of engine oil may suggest the product is a 5W-30, note, if there is no "W" between the 5 and the 30 it may not be a 5W-30. As an example, a SAE 5-30 is not the same as an SAE 5W-30.
The next 'code" to look for is the API Service Classification. Although it might appear complicated to understand at the start, it is really a simple system to get your arms around. Think of it this way, when cars were first built, the oil they required needed an API SA Service Classification. From there, it moved to SB, SC, SD, and so on (skipping only SI and SK). The current API Service Classification is SN.
