API 1509 Documents

API 1509 describes the voluntary API Engine Oil Licensing and Certification System (EOLCS) and explains to marketers how different API marks are licensed and displayed for the consumer. The current edition of API 1509 is now available and can be downloaded in pdf format. 

Downloads

API 1509, Engine Oil Licensing and Certification System, 21th Edition, February 2022

File Size: 3.00 MB

Current complete edition, includes Annexes E/F. For your convenience, see below links for extracted versions of each.

Annex E, API Base Oil Interchangeability Guidelines for Passenger Car Engine Oils and Diesel Engine Oils, 21st Edition, February 2022

File Size: 520 KB

Annex F, API Guidelines for SAE Viscosity-Grade Engine Testing, 21st Edition, February 2022

File Size: 401 KB