American Petroleum Institute. The primary oil and natural gas trade association in the United States. API operates a voluntary licensing and certification program that allows engine oil marketers to use the API Engine Oil Quality Marks if their products meet specific requirements. Service Category SL was first introduced in 2001 for use in gasoline engines and is not suitable for use in engines introduced after 2004. API continues to license engine oils against API SL and it is considered to be a current specification.
Oils that satisfy API Service Category SL are superior in performance to those meeting API SJ and earlier and can effectively lubricate engines calling for those Service Categories.
Due to newer API Service Categories (API SN PLUS, API SN, API SM) being suitable for use in applications specifying API SL many oils available today also claim to meet the requirements of API SL. This leads to API SL being seen to a wide range of lubricants of different performance levels and A measure of a fluid's resistance to flow. A fluid with a higher viscosity flows less easily. grades.
Where only API SL is claimed these oils are typically high High Temperature High Shear. A measure of a fluid’s resistance to flow under conditions resembling highly-loaded journal bearings in fired internal combustion engines, typically 1 million s–1 at 150°C. (≥ 3.5cP) SAE 10W-40, 15W-40 and 20W-50 based on API Group I or Group II base oils.
In some cases oils meeting API SL also carry an Energy Conserving claim to show that the oil has been formulated to improve fuel efficiency. These oils are typically low HTHS (≤ 3.5cP) SAE 5W-30 and 5W-20 based on API Group II base oils and coupled with International Lubricants Standardization and Approval Committee. A collaboration between the American Automobile Manufacturers Association (AAMA), Chrysler, Ford, GM, and the Japanese Automotive Standards Organization. ILSAC GF- engine oil specifications target fuel economy, emission system protection, and enhanced engine oil robustness. GF-3.
For more information on API SL, contact your Lubrizol representative.