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: