There’s been so much new information released about the upcoming oil categories that it might be easy to feel overwhelmed. The reality is the new API CK-4 and FA-4 oils — the final specifications that grew out of the PC-11 category — are not as daunting as many initially feared.

What’s the new category for?

If you’re asking why we even need a new oil category, the answer is simple. In part it’s about fuel efficiency, specifically the mandated fuel efficiency improvements for heavy-duty diesel engines. It’s also partly due to changes to the engines themselves that have made a new oil category necessary.

CJ-4, the current oil category, was introduced nearly 10 years ago. Since then, there have been some big changes to engine designs. The changes that have taken place — and will continue to take place — in heavy-duty diesel engines are placing more stress on oil, which lubricates, cools, cleans and protects the engine.

How Phillips 66® has been preparing

When developing these new oils it was critical they perform as well, if not better, than the current oils. The new CK-4 & FA-4 oils from Phillips 66 are specifically designed to outperform CJ-4 oils by exhibiting:

  • Improved oxidation stability
  • Increased resistance to aeration
  • Increased wear protection
  • Increased shear stability
  • Increased fuel economy

Phillips 66 has been developing and testing the new oils over the past four years. The formulations have gone through industry standard bench tests as well as engine test stands, with the final proof of performance resulting from field tests on more than 320 trucks collectively accumulating 57,000,000 miles! All of this to ensure the new oils meet (and exceed) the new standards. The first new oils from Phillips 66 will be available starting December 1, 2016.

How classification works

Before a new oil classification is announced, the American Petroleum Institute sets up a new category evaluation team to determine if a new oil is needed. Once they’ve decided, a new category development team determines the specifications and the test methods by which oils will be evaluated. After all this, the final phase is the implementation of the category.

Testing for performance

With API CK-4 and FA-4 some of the same tests that were used for CJ-4 applied, but other tests were changed or added. For example, the shear stability test had more stringent requirements. Two additional tests — one for oxidation stability and the other for aeration control — were completely new:

  • Shear stability measures the oil’s resistance to mechanical damage. Shearing can reduce an oil’s viscosity.
  • When aeration occurs in oil, tiny air bubbles occur in the oil and inhibit its ability to cool and protect the engine. This aeration can get worse under higher operating temperatures, like those experienced by the newer diesel engines.
  • Oxidation causes the oil to degrade and creates sludge. The oil’s viscosity can increase and corrosive wear can begin. Higher engine temperatures tend to increase oxidation.

CK-4 oils will replace the current CJ-4 oils; they are completely back-serviceable for all applications that required the use of CJ-4 oils. In addition to having the performance characteristics of the CJ-4 oils, CK-4 oils will have improved resistance to oxidation, better shear stability and more aeration control.

FA-4 oils on the other hand, will have lower viscosity grades and are designed for use with the next generation of diesel engines. They will help improve the fuel economy of those engines while still offering excellent protection. At this point, FA-4 oils have not been fully-endorsed by the engine builders as backwards compatible, so they may not be able to be used with all existing diesel engines. The engine builders will continue to evaluate these oils and refine their positions on backwards compatibility as more is learned. Most fleets and truck owners can expect to first use CK-4 oils and may eventually use FA-4 products as they purchase new assets in the years to come, or as allowed by their OEM.

A trusted name, investing in development

Phillips 66 will introduce an industry-leading line of CK-4 and FA-4 oils, including:

  • Fleet Supreme EC® for the general market — CK-4 15W-40 and 10W-30
  • Firebird EC an eco-friendly re-refined universal oil — CK-4 15W-40
  • Guardol ECT® a premium synthetic blend for severe service, extended service, on- and off-road — CK-4 15W-40 and 10W-30
  • Guardol® FE a premium synthetic blend for durable performance and fuel economy — FA-4 10W-30
  • Triton® ECT a full synthetic for extreme operating conditions on- and off-road  — CK-4 5W-40
  • Triton® Euro a full synthetic MB 228.51 approved universal oil — CK-4 5W-30
  • Triton® FE a full synthetic premium fuel efficient on-road universal oil — FA-4 5W-30
  • Triton® Arctic a full synthetic for Arctic climate on- and off-road — CK-4 0W-40

Tests of Guardol ECT® (CK-4) and Guardol® FE (FA-4) showed wear improvement over Guardol ECT® (CJ-4) in results from the Cummins ISM engine test run with SAE10W-30, low HTHS oil.

  • Guardol ECT®, a CK-4 oil, increased wear protection by 41.5% compared to the previous CJ-4 formulation.
  • Guardol® FE, a FA-4 oil, demonstrated a more than 40% improvement in controlling sludge wear in the engine compared to the previous CJ-4 formulation and also provided greater fuel economy.

A smooth transition

Phillips 66 is committed to ensuring you make a smooth transition from CJ-4 to the new CK-4 and FA-4 oils. Unlike some new regulations, there is only an upside to these modern oil upgrades, including increased performance and fuel efficiency, both without sacrificing wear protection and durability. The new oils from Phillips 66 significantly outperform the limit requirements of the category, and will give you coverage across a broad array of new engine designs and stringent OEM requirements.

The American Petroleum Institute is also doing its part to help ensure fleets get the oil they want and need. It’s introducing a special Service Symbol Donut to make sure fleets know which products are approved FA-4 oils. The new donut features a shaded section to differentiate FA-4 diesel oils from CK-4 oils. The CK-4 Service Symbol Donut will look the same as the current CJ-4 Donut.

More testing results from Phillips 66 are available at Contact with questions.