The trucking industry is preparing for a significant shift in diesel engine oil standards as part of the broader move toward reduced emissions and cleaner engine technology. A new generation of engine oils is expected to be available within the next 12 to 18 months, in anticipation of stricter emissions regulations scheduled to take effect in 2027.

This upcoming change is a collaborative effort between engine manufacturers and oil producers to align with environmental goals while ensuring engine performance, efficiency, and longevity.

Two New Oil Categories: CL-4 and FB-4

The new oil rollout will introduce two distinct categories designed to meet the different needs of both existing and future engines:

• CL-4: Designed as the successor to CK-4, this oil is backward-compatible and intended for use in current and older diesel engines. It offers enhanced protection for emission systems and improved oxidation stability, ensuring better performance without requiring engine upgrades.
• FB-4: This category is the next evolution of FA-4 and is targeted at next-generation engines that will launch alongside the 2027 emissions standards. FB-4 will be more fuel-efficient but will not be compatible with older engines. It is engineered for advanced powertrains that meet future emissions targets and prioritize performance with lower environmental impact.

Both oils are being designed to support longer engine life, reduce environmental impact, and align with the upcoming regulatory changes.

Preparing for 2027: Industry-Wide Alignment

The move toward CL-4 and FB-4 is part of an industry-wide push to ensure that emission standards are met without compromise. Engine manufacturers are already in the process of redesigning engines to meet the 2027 requirements. However, these engines will require oils with entirely new chemical properties, making the transition to CL-4 and FB-4 essential.

The development of these new oils is not just about meeting environmental regulations. It is also about ensuring that engines remain efficient, protected, and compliant under more demanding operating conditions.

Once the new oils are released to the market, CK-4 and FA-4 will be gradually phased out, ensuring that fleets and service providers shift toward the updated formulations.

Technical Challenges and Considerations

Creating a new oil standard that supports both environmental protection and engine durability is no small task. One of the key challenges is the reduction of certain chemical components, such as phosphorus, which can negatively affect emission systems. However, phosphorus is also vital for wear protection, so oil developers must strike a delicate balance.

To meet these demands, oil formulators are developing new additive technologies, including ash-free solutions, that continue to protect engines while remaining compatible with emissions systems.

Fleet operators and maintenance teams will need to ensure they’re using products that meet the new API-approved specifications. Choosing the correct oil category will be critical, not just for regulatory compliance, but also for engine longevity, fuel efficiency, and warranty protection.

What Fleets Need to Know

As 2027 approaches, fleets and owner-operators should begin preparing for the transition:

• Understand the difference between CL-4 and FB-4 and which applies to your fleet
• Work with your engine and oil suppliers to ensure compatibility
• Train maintenance teams on the proper use and handling of the new oils
• Verify that all oil products used meet official API standards

While the change presents some technical hurdles, it also represents a significant opportunity to improve fuel economy, reduce emissions, and enhance the lifespan of new diesel engines.

Final Thoughts

The introduction of CL-4 and FB-4 engine oils is a proactive step toward meeting the 2027 emissions regulations and improving overall engine performance. These new formulations will play a vital role in reducing the environmental footprint of diesel trucks while supporting the long-term health of modern powertrains.

As with any major industry change, preparation and education will be key. The earlier fleets begin adjusting to the new standards, the smoother the transition will be.

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