Shawn Whitacre, senior staff engineer, technology, Chevron

Ask the Expert: What is the difference between CK-4 and FA-4?

May 18, 2016
The primary difference in the two new API performance categories for heavy duty oil is with backward compatibility.

Q: What is the difference between CK-4 and FA-4?

A: The primary difference in the two new API performance categories for heavy duty oil is with backward compatibility. API CK-4 oils will be recommended for virtually all high-speed four stroke cycle diesel engines – including older engines that were using API CJ-4, as well as new engines that are currently being developed. The use of API FA-4 oils will be more limited and OEMs will not recommend them for use in most older diesel engines. This API FA-4 category is focus on the next generation of on-highway diesel engines that were designed to take advantage of the fuel economy advantage of the thinner oil.

Other differences include:

  • API CK-4
    • Viscosity grades include both SAExW-40 and xW -30 engine oils with >3.5 cP high-temperature high-shear (HTHS) viscosity
    • Higher level of wear and oxidation protection compared API CJ-4 oils
    • Improved shear stability
  • API FA-4
    • The same wear and oxidation protection required for API CK-4
    • Improved fuel economy
    • Applies only to SAE 10W-30 and SAE 5W-30 viscosity grades that have HTHS viscosity in the range of 2.9 to 3.2 cP
    • Developed to protect engine parts even with thinner oil films

Information provided by: Chevron

About the Author

Shawn Whitacre | Senior Staff Engineer, Technology, Chevron

Sponsored Recommendations

Are you aware of the hidden costs lurking behind ignored maintenance? This eBook reveals how neglecting upkeep can inate repair bills, induce downtime, and harm reliability. ...
Are your KPIs driving real fleet improvement? Learn how to set smarter, data-driven benchmarks, track success like top-performing fleets, and apply proven strategies to optimize...
Fullbay's fifth annual State of Heavy-Duty Repair compiles insights from almost 1,000 experts and over 3,500 shops. If you aren't leveraging these proven data points, your competition...
Quality body repairs on medium- and heavy-duty trucks depend on the use of specialized adhesives, sealers, and other allied materials. Unfortunately, many shops face challenges...