API SN Engine Oil Category
In 2010 the American Petroleum Institute introduced a new engine oil category under the name API SN and a new supplemental category called Resource Conserving.
The API SN category is an improvement over the API SM category in the following areas:
- High temperature deposit protection for pistons
- Better sludge control
- Better seal compatibility
- Aftertreatment compatibility
This means that API SN compares to API SM like this: