The API Service Symbol,
also known as the “Donut”
1. Performance Level:
Gasoline engine
(for cars, vans, and light trucks with gasoline engines):
Oils designed for gasoline-engine service fall under API’s “S” (Service) categories.
Look for current service categories SL and SJ.
See reverse for descriptions of current and obsolete API service categories.
Diesel engine oil categories
(for heavy-duty trucks and vehicles with diesel engines): Oils designed for diesel-engine service fall under API’s “C” ( Commercial) categories. Look for current categories CI-4, CH-4, CG-4, CF-4, CF-2, and CF.
2. Viscosity Grade:
The measure of an oil’s
thickness and ability to flow at certain temperatures. Vehicle requirements may vary. Follow your vehicle manufacturer’s recommendations on SAE oil viscosity grade.
3. EnergyConserving:
The “Energy Conserving”
designation applies to oils intended for gasoline-engine cars, vans, and light trucks. Widespread use of “Energy Conserving” oils may result in an overall savings
4. API Certification Mark:
An oil displaying this mark meets the current engine protection standard and fuel economy requirements of the International Lubricant Standardization and Approval Committee (ILSAC), a joint effort of U.S. and Japanese automobile manufacturers. Most automobile manufacturers recommend oils that carry the API Certification Mark.
The current and previous API Service Categories are listed below. Vehicle owners should refer to their owner’s manuals
before consulting these charts. Oils may have more than one performance level.
For automotive gasoline engines, the latest engine oil service category includes the performance properties of each
earlier category. If an automotive owner’s manual calls for an API SJ or SL oil, an API SM oil will provide full protection.
For diesel engines, the latest category usually – but not always – includes the performance properties of an earlier category.
