In 2010, the National Highway Traffic Safety Administration (NHTSA) required a reduction in greenhouse gas (GHG) emissions and mandated fuel economy improvements for medium and heavy-duty engines. The American Petroleum Institute (API) developed a new commercial engine oil performance category called Proposed Category 11, or PC-11. This guide explains API’s PC-11 categories and what to consider when determining the right oil for your heavy machinery.

Diesel C & F Categories

CK-4 Engine Oil

CK-4 is designed for off-highway equipment and is backward-compatible with CJ-4 and older Tier 4 engines.  It will accept diesel fuels with a 500 ppm sulfur rating, but a sulfur rating higher than 15 ppm has an increased chance of impacting exhaust after-treatment system durability. CK-4 oils are designed to protect against oil oxidation, engine wear, and catalyst poisoning.

FA-4 Engine Oil

FA-4 is for on-highway fleets and is better designed to aid with GHG emission standards. This oil is blended to a high-temperature, high-shear (HTHS) viscosity range to sustain emission control system durability. It’s not to be used with fuels with greater than 15 ppm sulfur ratings and isn’t interchangeable or compatible with C Category engine types. Some manufacturers may offer compatibility possibilities in the future, but it’s best to check the vehicle’s documentation to verify it can use FA-4 oils.

Classifications vs. Recommendations

Although API has classified new engine oils and most manufacturers have followed suit, the manufacturer’s recommendations are the right way to go. Some manufacturers are using specialized emissions-reduction technologies and have created their own specific oils to work with their engines. Although the CK-4 and FA-4 oils may work, the manufacturer’s oil should meet or exceed these specifications while offering other benefits, such as acid and soot reduction.

If you’re wondering what kind of engine oil is best for your vehicle, contact the experts at Kennedy Oil Co Inc in High Point, NC. They’ve provided oil and fuel delivery for more than 80 years and can guide you in choosing what’s right for your heavy machinery. Visit their website to learn more about their services or call (336) 885-5184 to speak with a knowledgeable technician today.