Motor oil is essential for keeping a car running smoothly. But not all motor oils are created equal, and the standards they must meet depend on where they are produced and sold. Here we explore the differences between American and European petroleum standards and how they affect the quality of motor oil.
American Petroleum Institute (API) standards
The American Petroleum Institute (API) sets the standards for motor oil in the United States. They make sure motor oils meet defined performance and quality requirements, and are divided into two groups: service categories and resource conserving.
Service categories
API service categories make sure motor oils meet the performance requirements of different engine types, for example API SN for petrol engines and API CK-4 for diesel engines.
Resource conserving
API Resource Conserving standards make sure motor oils are formulated to improve fuel economy and reduce emissions, for example API SN Plus and API SP.
European Automobile Manufacturers' Association (ACEA) standards
ACEA sets the standards for motor oil in Europe. They are divided into three main categories.
ACEA A
For petrol engines, making sure motor oils meet the performance requirements of these engines.
ACEA B
For diesel engines, making sure motor oils meet the performance requirements of these engines.
ACEA C
For engines fitted with after-treatment systems such as diesel particulate filters and catalysts, making sure motor oils protect both the engine and the emissions system.
Differences between American and European standards
Viscosity
American standards tend to favour lower-viscosity oils, while European standards tend to favour higher-viscosity oils.
Additives
American standards allow a greater variety of additives, while European standards tend to be more restrictive.
Emissions
European standards are more stringent on emissions than American standards.
Conclusion
Both American and European standards aim to make sure motor oils meet defined performance and quality requirements, but there are notable differences. American standards favour lower viscosity, a wider range of additives and less stringent emissions rules. European standards favour higher viscosity, more restrictive additives and stricter emissions rules. Always check the standard your vehicle requires and make sure your oil meets it.
