Low-vis Grades to be Added to GF-6


North America’s automotive and lubricant industries are continuing their steady march to lower viscosity grades for gasoline-powered light-duty vehicles, undertaking this time to add 0W-12 and 0W-8.

The Auto/Oil Advisory Panel, made up of representatives from the International Lubricant Standardization and Approval Committee and the American Petroleum Institute’s Lubricants Group, accepted last week a request to incorporate both grades into ILSAC GF-6, the latest oil category for the North American market.

As requested by API, the panel agreed to fast track the work, aiming to finish in time for API to begin licensing oils of those viscosities by the end of the year. To meet that aggressive timeline, the groups plan to adopt a fuel economy test developed recently by the Japanese Automotive Standards Organization, API said.

Changes to GF-6 will be carried over to its companion category, API SP.

Lowering viscosity has been the lube industry’s main approach to increasing engine oil contributions to better fuel economy. Lighter oils reduce friction within the engine by easing oil pumpability, reducing churning losses and forming thinner oils films.

In the 1990s, 10W-30 was the most popular viscosity grade in North America. Since then the market shifted to mostly 5W-30 and 5W-20 oils, in an effort to reduce fuel consumption and carbon dioxide emissions. Now demand is shifting to 0W- oils, which were pioneered by Honda.

ILSAC made 0W-16 part of its system by including the grade in ILSAC GF-6B, one of two subcategories under GF-6, which was introduced in 2020.

ILSAC and API have launched the process of developing the market’s next light-duty oil update, ILSAC GF-7, but the target date for introducing it is not until 2028, and automakers wanted 0W-12 and 0W-8 available much sooner.

In a news release issued by API, the senior manager of the organization’s Engine Oil Licensing and Certification System, Jeff Harmening said any viscosity grades added to GF-6 need to be covered by a fuel economy test but that there are not yet a North American method capable to serving this role.

“The existing GF-6 fuel economy tests have not demonstrated the ability to accurately measure fuel economy in these ultra-low viscosity grades,” Harmening said. “Therefore, the API recommends reliance on a recently published fuel economy test standard from the Japanese Automotive Standards Organization.”

The Japanese test, JASO M366, is conducted on a fired engine stand that is available at independent laboratories in the United States, the news release said. It added that the test has guidelines for base oil interchange and viscosity grade read across.