Engine Oils
1 800 255 4417
www.castrol.com/GPS
Background & Properties
Industry Specifications
July 2017
History
Over the years, the drivers for change in diesel engine oils have been based upon the U.S. Environmental Protection
Agency (EPA) regulations for exhaust gas emissions. These changes occur every few years. To be able to meet ever-
tightening limits, engine manufacturers must change engine designs; these design changes almost always put
additional stresses on the oil, therefore calling for new engine oil service categories. With particulate matter (PM) and
nitrogen oxide gases (NOx) already at very low levels, the newer exhaust emission regulations address the reduction of
greenhouse gases (GHG), especially carbon dioxide (CO
2
). The CO
2
limit has led to the development of the next
generation heavy duty (HD) engine oil for low GHG engines. The first licensing of the new American Petroleum
Institute (API) specifications, CK-4 and FA-4, began on December 1, 2016.
A 2
