The American Petroleum Institute (API) has been setting the standards for motor oil quality since its inception. Over the years, the API grades have evolved, adapting to technological advancements and ever-changing engine requirements. In this blog post, we’ll provide a chronological overview of the API grades and how they’ve developed over time.
API Grades for Gasoline Engines
In the 1930s, API introduced the first series of classifications for gasoline engine oils, starting with the SA grade. Each new category marked an improvement over the previous one, offering better engine protection and performance. Here’s a brief overview:
- SA: Introduced in the 1930s, this was the original grade for minimally refined motor oils.
- SB: Developed in the 1950s, this grade was for engines of that era.
- SC: Introduced in 1964, suitable for engines built in 1964-1967.
- SD: Developed in 1968 for engines from 1968-1971.
- SE: Introduced in 1972 for engines from 1972-1979.
- SF: Developed in 1980 for engines built in the 1980s.
- SG: Introduced in 1989 for engines from 1989-1993.
- SH: Brought in 1993 for 1994 model-year engines.
- SJ: Introduced in 1996 for 1997-2001 engines.
- SL: Developed in 2001 for engines up to 2004.
- SM: Launched in 2004 for engines up to 2010.
- SN: Introduced in 2010 and suitable for engines built in 2011 or earlier.
- SP: The latest grade, introduced in 2020, is suitable for all engines currently on the road.
API Grades for Diesel Engines
For diesel engines, the classification system began with the CA grade. Similar to gasoline engine oils, each subsequent grade marked an improvement over the previous. Here’s a quick rundown:
- CA: Introduced in 1949 for moderate-duty engines.
- CB: Developed in 1961 for mild-duty engines.
- CC: Introduced in 1961 for moderate to severe duty engines.
- CD: Developed in 1955 for high-speed, four-stroke engines.
- CE: Introduced in 1985 for high-speed, four-stroke engines.
- CF-4: Developed in 1990 for high-speed, four-stroke engines.
- CG-4: Introduced in 1995 for severe-duty, high-speed, four-stroke engines.
- CH-4: Developed in 1998 for high-speed, four-stroke engines.
- CI-4: Introduced in 2002 for high-speed, four-stroke engines.
- CJ-4: Developed in 2006 for high-speed, four-stroke engines.
- CK-4: The latest grade, introduced in 2016, is suitable for all current vehicles on the road.
At Greyhound Lubricants, we are committed to providing high-quality, API-certified motor oils. We ensure that every product we offer meets the current API grade requirements, offering the best protection for your engines.
Understanding the history and evolution of API grades can provide you with a better appreciation of the advancements in engine oil technology. When choosing your engine oil, consider its API grade. If you have any questions, the team at Greyhound Lubricants is ready to assist. Remember, investing in high-quality engine oil is investing in the performance and longevity of your vehicle.
