American Petroleum Institute (API) announced the approval of improved performance standards for engine oils that will provide greater protection and fuel efficiency for today’s gasoline-engine ...

Engine oil products that have the API category and ratings, including the S on their containers, have undergone the voluntary Engine Oil Licensing and Certification System - EOLCS from the API.

These API engine oil categories, CJ-4 and CK-4, differ in their performance attributes, which contribute to a vehicle’s overall fuel economy and operating capacity.

In order to meet the U.S. EPA's 2007 on-highway emission standards for particulate and NOx, all diesel engines will require diesel particulate filters (DPFs) and cooled exhaust gas recirculation (EGR) ...

With test parameters established for the proposed new oils, oil companies began developing formulations that would satisfy the new API standards and overcome the perceived shortcomings of CJ-4. During ...

API CI-4 oils are pivotal components in maintaining diesel engine durability using cooled EGR. API CI-4 is a higher quality oil than the previous diesel oil categories, so it will provide engine ...

Gen III then submitted its first Group III based 5 W-30 PCMO formulation and ReGen III product to API’ s Engine Oil Licensing and Certification System.

Development of “IDEMITSU IFG Plantech Racing,” the world’s first API-certified engine oil with racing performance made from more than 80% plant-based raw materials (August 7, 2024).

With so many options for motor oil, it can be overwhelming finding the perfect option for your vehicle. We go over the details to help you understand which engine oil is best for your car.

There's a lot of information on the packaging for your engine's motor oil, but the S designation may be one of the most important to look for.