There are two symbols that appear on the label of an oil bottle which identify the oil as licensed and certified. We have the API Service Symbol known as the "donut", and the API Certification Mark known as the "starburst". The American Petroleum Institute operates this certification program which is the Engine Oil Licensing and Certification System (EOLCS). This system is a coordinated effort between the oil industry and the engine manufacturers. The following organizations are involved is this process:
= American Automobile Manufacturers Association
= Engine Manufacturers Association
= American Society for Testing and Materials
= Society of Automotive Engineers
= American Petroleum Institute
Let's take a look at the three sections of this symbol.
(1) Top Section "API Service SJ"
The classification indicates the type of engine and service classifications as follows:
= SJ for gasoline engines in cars, vans, and light trucks. This designation was introduced October 15, 1996.
= SH is superseded by SJ and will not be valid after August 1, 1997 except when used in combination with certain C categories.
= CG-4 for high-speed, four-stroke cycle diesel engines used in highway and off-road applications.
= CF-4 for high performance, four stroke and turbo charged diesel engines.
= CF-2 for two-stroke diesel engines.
= CF for off-road, indirect injection diesel engines using high-sulfur fuel.
= CE for many high performance, four-stroke and turbo charged diesel engines. This classification was discontinued after December 31, 1995.
= CD-II for two-stroke diesel engines. This classification was discontinued after December 31, 1995.
= CD for heavy-duty turbo charged diesel engines. This classification was discontinued after December 31, 1995.
(2) Center Section "SAE 5W-30"
This section of the "donut" refers to the viscosity of the oil as designated by the Society of Automotive Engineers (SAE). An engine oil classified as "5W-30" is a multi-grade oil where the viscosity of the oil changes with the operating temperature of the engine. The viscosity of a single-grade oil designated by one number would not change with the operating temperature of the engine. Refer to the owners manual for the recommended viscosity grade for your vehicle.
The first number "5" refers to how well the oil will flow at engine start-up. A lower number will have a lower viscosity, and the oil will flow faster through the engine when first started. This is very important in cold weather starts as most engine wear occurs at this time. It is important to note that synthetic oils have much better low temperature flow characteristics.
The "W" designates the oil as having good flow capability for cold weather starts. Think of winter and you will remember the definition for "W".
The second number "30" indicates the high temperature viscosity of the oil when the engine has reached operating temperature.
(3) Bottom Section "Energy Conserving"
This refers to the fact that the engine oil has passed designated tests which certify the oil as having energy conserving properties. You may see "Energy Conserving II" which designates the oil as having better energy conserving properties then "Energy Conserving".
After August1, 1997 only SJ oils will be designated as "Energy Conserving". The test for SH in combination with "Energy Conserving" and "Energy Conserving II" will not exist.
This designates the type of engine for which the oil has been formulated. The "FOR GASOLINE ENGINES" indicates that the oil has been formulated for use in light-duty gasoline engines. The "CERTIFIED" means that the company selling the oil meets all the requirements, and has signed a formal licensing agreement with API.