English 
Español
Français
PortuguêsWhich oil is right for you?
API’s Certification Mark and Service Symbol identify quality motor oils for gasoline- and diesel-powered vehicles. Oils displaying these marks meet performance requirements set by U.S. and international vehicle and engine manufacturers and the lubricant industry. More than 500 companies worldwide participate in this voluntary program, which is backed by a marketplace sampling and testing program.
The API Certification Mark, also known as the “Starburst”
An oil displaying this mark meets the current engine protection standard and fuel economy requirements of the International Lubricant Specification Advisory Committee (ILSAC), a joint effort of U.S. and Japanese automobile manufacturers. Automobile manufacturers recommend oils that carry
the API Certification Mark. See the ILSAC STANDARD FOR PASSENGER CAR ENGINE OILS chart on the next page for descriptions of current and obsolete ILSAC standards.
The API Service Symbol, also known as the “Donut”
1. Performance Level
Motor oils designed for cars, vans, and light trucks with gasoline engines fall under API’s “S” (Service) categories. Motor oils designed for heavy- duty trucks and vehicles with diesel engines fall under API’s “C” (Commercial) categories. Please see the Gasoline Engines and Diesel Engines charts on the next pages for descriptions of current and obsolete API service categories.
2. Viscosity Grade
The measure of an oil’s ability to flow at certain temperatures. Vehicle requirements may vary. Follow your vehicle manufacturer’s recommendations on SAE oil viscosity.
3. Resource Conserving and Energy Conserving
These designations apply to oils intended for gasoline-engine cars, vans, and light trucks. Widespread use of “Resource Conserving” or “Energy Conserving” oils may result in an overall savings of fuel in the vehicle fleet as a whole.
4. Multiple Performance Levels
Oils designed for diesel engine service might also meet gasoline engine service. For these oils the designation is “C” category first followed by the “S” category. “C” category oils have been formulated primarily for diesel engines and may not provide all of the performance requirements consistent with vehicle manufacturers’ recommendations for gasoline- fueled engines.
5. The API Service Symbol with CI-4 Plus
The “CI-4 PLUS” designation identifies oils formulated to provide a higher level of protection against soot-related viscosity increase and viscosity loss due to shear in diesel engines. When originally introduced, CI-4 PLUS identified CI-4 oils meeting a higher level of performance. CJ-4 oils include all CI-4 PLUS performance requirements. CI-4 PLUS appears in the lower portion of the API Service Symbol “Donut”.
GET MORE FROM YOUR MOTOR OIL
Follow your vehicle manufacturer’s oil change recommendations. This includes using recommended SAE oil viscosity and ILSAC or API performance standard.
If you find it necessary to mix brands of oil, use same viscosity grade and API service category to maintain performance.
Properly dispose of used oil. Learn more about recycling used oil at www.recycleoil.org. Go to www.earth911.com/ recycling/used-motor-oil- and-filters for used oil collection center locations.
Ask for API- licensed oil whenever you have your oil changed.
Look for API Certification Marks every time you buy motor oil.
For more information visit MotorOilMatters.org.
Learn about chemical additives in motor oil at AmericanChemistry.com.