A Change is Going to Come

New engines mean new oil formulations and the next generation of engines is no exception. Castrol tell us new oil classifications will be coming on line in the next year or two.

Everyone in trucking understands the vital role the industry plays in the prosperity of Australia. The country’s low population density and long distances between markets means the Australian people are heavily reliant upon road freight. In fact, the trucking industry carries three quarters of Australia’s domestic freight.

The trucking industry has always been complex and those who adapt to the changing market conditions can thrive and prosper. Economic, technological and regulatory factors along with strong competition all impact on the industry and its operators. One such big technological change that is heading towards the industry is a major shift in the lubricant technology, the lifeblood of our prime movers.

Proposed Category 11 (PC-11) is a new category for heavy-duty diesel engine oils as classified by the American Petroleum Institute (API). Castrol suggests, in this change is hidden something much bigger. It’s not just a category change, it’s a change which helps protect the environment and our future. It is the biggest change in heavy-duty engine oils in about 10 years, with the last change being back when API introduced CJ-4 in 2006.


Improving fuel economy and reducing environmental impact are the goals driving the category changes. The next level of exhaust emission controls set by the US EPA are mandated to commence in 2017. These differ from the exhaust regulations of the past, in concentrating more on carbon dioxide emissions than the particulate matter and nitrogen oxides, they targeted in the past.

The changes mandated by the US EPA are echoed in the development of Euro 7 for truck emissions in Europe and the next stage of the New Long Term emission controls in Japan. These will all need a supporting oil standard to handle the new technology. According to Castrol, the API represents the industry collective wisdom on everything, from drill to environment protection, and embraces proven sound engineering and operating practices, and safe, interchangeable equipment and materials. Leading lubricant manufacturers like Castrol are a part of API.



The change in new regulations coming into effect in 2017 is driving the need for the next generation of oils to address factors like:

  • Technical advancements in diesel engine designs.
  • Improved protection from higher engine operating temperatures.
  • Improved protection from engine oil shearing.
  • Need for reduced fuel usage with the new spec.


PC-11 is a unique spec change in heavy-duty engine lubrication in the way that it’s split into two different specifications

  • API CK-4 is set to replace API CJ-4 and previous categories, delivering higher performance levels, but is backwards compatible for older engines.
  • API FA-4 is highly advanced lower viscosity oil that delivers better fuel economy in new technology diesel engines.

API CK-4 and FA-4 present tough challenges for the next generation of diesel engine oils and how they must perform, particularly in advanced modern engines. Three tests in particular define these performance challenges.

The oxidation control test looks at oxidation, which is a chemical reaction of oil with oxygen (from air) which significantly deteriorates engine oils over time. It is accelerated by high stress operation conditions such as the high temperatures we see in modern engines. Oxidation control is becoming increasingly important, as advanced heavy-duty engines are designed to run hotter in the drive for higher performance and efficiency. Oxidation leads to increasing oil viscosity and deposit formation, which results in reduced ability to flow, thus decreasing engine protection and negatively impacting engine fuel efficiency.

The CK-4 diesel engine oils are blended to deliver outstanding oxidation resistance to meet the demands of hard working equipment in Australia.

The aeration control test is also important, aeration or foaming is a physical process in which small bubbles of air as foam become entrapped in the lubricant. Aeration directly affects the intended lubrication properties of oil. A high level of entrapped air will degrade the ability of the oil film to protect engine parts, potentially causing engine wear and ultimately meaning greater costs for operators.

The CK-4 engine oils will meet or exceed the new category test for aeration control, to deliver higher ever levels of engine protection.

There is also the shear stability test necessary because multigrade engine oils are formulated with viscosity modifiers, additives which control oil viscosity under different operating temperatures. Under stress, these molecules may ‘shear’, affecting their ability to control viscosity.

Shear stability is a measure of the ability of an oil to stay in SAE viscosity grade ie SAE 30 stays as an SAE 30 after repeated use. The viscosity specs of any engine oil are precisely matched to the application and operating conditions it is recommended for. Shearing of the viscosity modifiers means the oil can become thinner and less protective, ie an SAE 30 grade could drop down to SAE 20 leading to compromised engine protection.

The API FA-4 engine oils are formulated with a unique viscosity modifier which significantly improves the oil’s shear stability, for new levels of stay-in-grade performance, and better protection for the modern heavy-duty diesel engines.



Lubricant manufacturers like Castrol have been doing extensive product trials on their API CK-4 products right here in Australia to ensure their new products stand up to the rigorous work conditions that Australian fleets work with. They have been doing trials with leading mixed fleets including Cummins, Detroits and Macks and pushing the oil to its absolute limits.