PC-11: Overview of the API specification change  

The American Petroleum Institute’s (API) heavy-duty diesel engine oil category (commonly referred to as "Proposed Category 11" or "PC-11") is designed to help reduce emissions and boost fuel economy. ExxonMobil wants you to be knowledgeable on this industrywide change. Get all of the key facts below.
  • What is PC-11 all about?

    CK-4 and FA-4 oil drop icons

    The development of an oil category 

    PC-11 established two diesel engine oil specifications – one with backward compatibility for older engine technology ("CK-4") and one for use with newer engine technology ("FA-4").

    FA-4 oils aim to improve fuel efficiency and reduce greenhouse gas emissions. CK-4 oils are designed as direct replacements to CJ-4 oils, offering enhancements in oxidation resistance, shear stability and aeration control.

  • How does PC-11 affect owner-operators and fleets?

    Fleet Operator with truck

    Switching engine oils

    PC-11 does not change the best practices that help drive the success of owner-operators and fleets. It’s also important to note that PC-11 does not affect every business in the same way.

    Some owner-operators and fleets with older equipment may see only a small impact from PC-11 – switching their CJ-4 oils to the enhanced CK-4 oils. In comparison, fleets with a combination of older and newer equipment may choose to stock both CK-4 and FA-4 oils until the older units are cycled out of the fleet.

    Owner-operators and fleets operating newer equipment with advanced engine technology should follow original equipment manufacturer recommendations, but they also may decide to upgrade to FA-4 oils if they are looking to improve fuel economy. We anticipate that some owner-operators and fleets will want to be early adopters of both the advanced engine technology and high-performance FA-4 oils.

  • When did PC-11 arrive?

    Calendar icon for 2016 year


    PC-11 is here. CK-4 and FA-4 diesel engine oils are in market.

  • Where is PC-11 being applied?

    Map of North America highlighting US, Canada and Mexico

    North America

    There is a global impact with PC-11, but the primary applications are in the United States, Canada and Mexico.

  • Why do we need another oil specification?

    3/4 full fuel gauge icon

    Emissions and fuel efficiency standards

    Industry standards are calling for vehicle and engine improvements capable of:

    • Reducing carbon dioxide and greenhouse gas emissions.
    • Enhancing fuel efficiency.
    • Maintaining engine durability while improving oxidation resistance, shear stability and aeration control.

    These improved engine designs require commercial vehicle engine oils with performance capabilities far exceeding those of CJ-4 oils.

  • How were the two PC-11 oils created?

    PC-11 Oil in beaker

    Research and development

    The PC-11 diesel engine oils have gone through substantial research and development, ensuring the lubricant technology meets new performance targets while improving engine wear protection. After being proven via extensive field testing, the PC-11 (CK-4, FA-4) Mobil Delvac™ engine oils were announced on Sept. 20, 2016.

    As of June 2017, we have accumulated more than 50 million miles of testing data on our CK-4 and FA-4 formulations. We are still accumulating more than 1.5 million miles a month of additional testing data with select fleet partners. Our current field testing includes about 200 trucks.

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