FAQs

PC-11 (Proposed Category 11) is the temporary term API used to identify the oil standards now labeled as API CK-4 and API FA-4 while the standards were in development. CK-4 and FA-4 will begin appearing in the API Service Symbol Donut on December 1, 2016.

CK-4 and FA-4 provide improvements in the following areas:

• Wear protection
• Oxidative stability
• Aeration control
• Protection against soot-related viscosity increase
• Emission system protection
• Piston deposit control
• Low- and high-temperature property control

CK-4 oils are designed for on-highway and non-road diesel engines currently in use. These oils are backward compatible, which means they can be used in applications where CJ-4, CI-4 with CI-4 PLUS, CI-4, and CH-4 oils are recommended. During its development, CK-4 was referred to as PC-11A.

Before switching to CK-4, check with your engine manufacturer and remember to use the viscosity grade recommended for your engine.

FA-4 oil provides the same benefits as CK-4 oil — superior wear and oxidation protection and enhanced shear stability — but will also include lower viscosity grades designed for next-generation diesel engines to help reduce emissions without sacrificing engine protection. However, FA-4 oils are neither interchangeable nor backward compatible with CK-4, CJ-4, CI-4 with CI-4 PLUS, CI-4, or CH-4 oils.

Some engine manufacturers may recommend FA-4 oils for their older engines, but operators must confirm the recommendation before using the oils. In many cases, engine manufacturers will only recommend FA-4 for newer engines.

The new products will be available through the same distribution channels that supply CJ-4 products.

Products meeting the CK-4 or FA-4 specification can be sold beginning December 1, 2016. Consult your supplier for availability.

CK-4 oils are backward compatible, so they can be used where CJ-4 or earlier diesel standards are recommended. Click on your vehicle type to learn more:

Big Rigs
Diesel Pickups
Heavy Duty Construction Equipment
Agricultural Equipment

FA-4 oils are not backward compatible and should only be used where recommended. Choose your vehicle type to learn more:

Big Rigs
Diesel Pickups
Heavy Duty Construction Equipment
Agricultural Equipment

The CK-4 standard is the replacement for CJ-4, but CJ-4 will remain a licensable API standard for the foreseeable future. Keep in mind that CK-4 oils are backward compatible and provide superior protection against wear and oxidation along with enhanced shear stability.

Check with your engine manufacturer before moving up to CK-4, but most manufacturers recommending CJ-4, CI-4 with CI-4 PLUS, CI-4, or CH-4 oils will likely recommend CK-4 for their diesel engines in use today.

Look for the API service symbol donut with “CK-4.” The CK-4 category will appear first, often followed by CJ-4, CI-4, and CH-4. The donut should look something like the one shown below.

Look for the modified API service symbol donut with “FA-4.” The donut could be in a variety of colors, but it should look like the one shown below.

Engine manufacturers are expected to recommend API CK-4 oils for most on-highway engines using CJ-4 and earlier categories because the standard is backward compatible, but some manufacturers have begun recommending FA-4 for some of their on-highway engines. Manufacturers will also start recommending FA-4 for their new engines. Check with your manufacturer if you have any questions about which oil you should use in your big rig.

Engine manufacturers are expected to recommend API CK-4 oils for non-road diesel engines in heavy duty equipment using CJ-4 and earlier categories. Learn more here.

Engine manufacturers are expected to recommend API CK-4 oils for non-road diesel engines used in agricultural equipment. Learn more here.

Engine manufacturers are expected to recommend API CK-4 oils for many diesel pickups but check with your manufacturer before making the switch. Learn more here.