API CK-4 describes oils for use in high-speed four-stroke cycle diesel engines designed to meet 2017 model year on-highway and Tier 4 non-road exhaust emission standards, as well as for previous model year diesel engines.

These oils are formulated for use in all applications with diesel fuels ranging in sulfur content up to 500 ppm. However, the use of these oils with greater than 15 ppm sulfur fuel may impact exhaust after-treatment system durability and/or oil drain interval. API CK-4 oils are especially effective at sustaining emission control system durability where particulate filters and other advanced after-treatment systems are used.

The main physical and chemical requirements for API CK-4 oils are shown below:

Requirement Method Unit Limit
HTHS viscosity ASTM D4683 cP ≥ 3.5
Sulphated Ash ASTM D874 %wt ≤ 1.0
Phosphorus ASTM D4591 %wt ≤ 0.12
Sulphur ASTM D4591 %wt ≤ 0.4
Evaporation loss (NOACK) ASTM D5800 % ≤ 13

API CK-4 oils are designed to provide enhanced protection against oil oxidation, viscosity loss due to shear, and oil aeration as well as protection against catalyst poisoning, particulate filter blocking, engine wear, piston deposits, degradation of low- and high-temperature properties, and soot-related viscosity increase. These oils exceed the performance criteria of API CJ-4, CI-4 with CI-4 PLUS, CI-4, and CH-4 and can effectively lubricate engines calling for those API Service Categories. When using CK-4 oil with higher than 15 ppm sulfur fuel, consult the engine manufacturer for service interval recommendations.

For more information on API CK-4, contact your Lubrizol representative.

For a deeper dive into specifications, see the Lubrizol Ready Reference Guide, the industry's go-to resource for understanding fuel and lubricant performance principles and requirements.