API (American Petroleum Institute) "Donut"

This is the most informative and perhaps the least understood symbol on motor oil containers. Usually on the back label, this "donut" as it is called, contains an exact reference to the performance rating of the oil, a fuel economy rating and viscosity grade of the oil.

In the center of the symbol is the familiar SAE viscosity rating, above this is the API service category or performance rating of the oil. The service category is a two letter code which describes both the intended application ofthe product (e.g. "S" is for all gasoline-fueled engines and "C" is for diesel engines) and the performance rating. The performance rating, the second letter, represents the evolution of motor oil technology. The first level of performance, applicable in the 1930s and earlier is represented by the letter "A," the most technologically advanced performance level available is represented by the letter "J." If you have followed all of this, the meaning of API SERVICE "SJ" in the donut should be clear, i.e., gasoline-fueled and highest performance available to date. In the lower portion of the donut is an area reserved for statements about the oil's energy conserving properties. If you see a reference to conserving energy, it means this oil is formulated to conserve energy or save gasoline. In other words the oil is designed to be fuel efficient.

Motor oils that meet API SH specifications and offer the highest level of fuel economy can display this "starburst" symbol to show they meet or exceed the most recent American and Japanese warranty requirements. The symbol was developed jointly by the motor oil and automotive industries to make it easier for consumers to identify motor oils that meet the minimum requirements of the automakers. Although the technical requirement to display the symbol will change to accommodate new car designs, the symbol itself will not change. This system is administered by API in cooperation with the International Lubricant Standardization and Approval Committee (ILSAC), which represents American and Japanese automobile manufacturers.