If you’ve ever wondered whether the oil you put in your engine is actually up to the task, the American Petroleum Institute has just made that decision a little easier. The American Petroleum Institute has rolled out the 23rd edition of API 1509, the industry’s benchmark for engine oil certification. This update fine-tunes the Engine Oil Licensing and Certification System (EOLCS), ensuring that every bottle carrying the API seal meets the highest standards for performance and protection.

“API 1509 plays a crucial role in managing the API Engine Oil Licensing and Certification System (EOLCS), providing oil marketers with guidelines on licensing and proper display of the API Engine Oil Quality Marks for consumers,” says Bill O’Ryan, Senior Manager, API EOLCS/DEF. “The updated standard assures consumers that American Petroleum Institute-certified engine oils are the highest quality option for their vehicles.”

At its core, the EOLCS is a voluntary certification program that gives oil marketers a way to prove their products meet API’s stringent performance standards. This latest update clarifies how engine oil should be licensed, labeled, and marketed — while also tightening enforcement to prevent misleading claims. We’ve discussed oil standards before, and their importance in making sure your oil meets specifications.

What’s In API New Edition?

The 23rd edition of API 1509 lays out:

• Stronger quality control for American Petroleum Institute-certified oils
• Clearer licensing and marketing rules for oil marketers
• Defined procedures for developing new oil standards
• Better enforcement to ensure products actually meet American Petroleum Institute’s standards

With API standards developed through the American National Standards Institute (ANSI), this update also strengthens the certification’s credibility at state, federal, and international levels.

Why This Matters

The American Petroleum Institute isn’t just setting standards—it’s shaping an industry that keeps America’s 283 million registered vehicles running. The institute represents 600+ companies in the natural gas and oil industry, which supports nearly 11 million U.S. jobs. Through its Energy Excellence program, the American Petroleum Institute continues to push for safer, cleaner, and more efficient oil production.

Since 1919, the American Petroleum Institute has written over 800 standards for everything from refining to emissions control. This latest update to API 1509 keeps the bar high, ensuring that when you see an API certification on your engine oil, you know it’s a product you can trust.