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New Diesel Engine Oil Specifications are Necessary to Protect Engines in Diesel-powered Pickup Trucks


API CK-4 and FA-4 Oils are designed for current and future engines

By Kevin Ferrick, Senior Manager for Engine Oil Licensing, API 

With the arrival of two new diesel engine oils categories in December of 2016, drivers of diesel pickup trucks need to learn about their application. API CK-4 oils succeeded CJ-4 engine oils and are backward compatible diesel oils. Backward compatible means CK-4 may be used where CJ-4, CI-4 with CI-4 PLUS, CI-4, CH-4, and earlier service categories are recommended. API FA-4, on the other hand, is a new arrival intended for engines built beginning with the 2017 model year. It is important to note, however, that diesel truck owners should always check with their engine manufacturers to confirm that they should use one of the new categories. There are currently 580 CK-4 oils and 77 FA-4 oils licensed by API and more are expected.

These new service categories improved upon existing API standards by providing enhanced protection against oil oxidation and protection against engine wear, particulate filter blocking, piston deposits, and degradation of low- and high-temperature properties.

Why new engine oil specifications are needed for diesel engines

Diesel engine technology has changed significantly since API introduced its last diesel engine oil specification, CJ-4, in 2006. Today’s engines run more efficiently, generate more power, and feature different hardware. For example, many use high pressure, common-rail injection systems that are now widely used to improve combustion efficiency; advanced turbocharger technology to increase power output; and the use of diesel particulate filters and selective catalytic reduction to decrease or prevent emissions of harmful oxides of nitrogen and particulate matter.

Oils now have to lubricate ever more effectively, while also cooling, cleaning, and protecting newer engines effectively. Lower viscosity oils, such as 10W-30, are expected to be one tool used to help deliver fuel economy savings while still providing the protection and durability needed. The new generation of high-performing CK-4 and FA-4 diesel engine oils provide engine manufacturers with the protection they need as they design cleaner, more fuel-efficient diesel engines.

Benefits of New Engine Oils

CK-4 provides improved shear stability, oxidation resistance, and aeration control over CJ-4 in the familiar SAE 15W-40 and 10W-30 viscosity grades. FA-4 provides similar protection to CK-4 oils, but in lower viscosity grades to meet the needs of next-generation diesel engines being built for the 2017 model year and onwards. FA-4 oils meet the same performance measures as CK-4 but they also help increase fuel economy in engines designed for the lower viscosity FA-4 grades. Key improvements to the new oils include the following:

  • Shear Stability – Shear stability is the resistance of oil molecules to shearing or breaking down under extreme stress inside the engine. Shear causes oil to decrease to a lower viscosity, and excessive viscosity loss could affect how well the oil can protect the engine. CK-4 and FA-4 oils with have improved shear stability compared to CJ-4 oils. 
  • Oxidation Stability – Oil oxidation is one of the main reasons for oil breakdown and it occurs more readily under higher engine operating temperatures. With many newer engines running hotter, CK-4 and FA-4 standards deliver improved oxidation stability versus CJ-4 oils.
  • Aeration – Aeration is the entrainment of air bubbles in the oil, which can limit the ability for oil to cool and protect the engine. Newer engines with higher operating temperatures and pressures can increase the amount of air trapped in oil. As oil is more regularly used as a hydraulic fluid for valve-train actuation, this task can be compromised by aerated oil. CK-4 and FA-4 oils provide greater protection against aeration.
  • Fuel Economy – CK-4 oils are being called “High HTHS” engine oils because their viscosities are the same as those found in CJ-4 oils. In contrast, FA-4 oils are being called “Low HTHS” oils because their viscosities are lower. These Low HTHS oils have been developed to provide engine manufacturers with a tool that will help them meet more stringent fuel economy and greenhouse gas emissions requirements. Lower viscosity oils are known to help increase fuel efficiency, which in turn helps to reduce greenhouse gas emissions.

Increases in fuel economy can result in significant reductions in fuel consumption and carbon dioxide emissions. The reduction in CO2 output arises from the engine’s running more efficiently and consequently putting less CO2 into the environment.

To help people differentiate between the two new oils, API developed a special Service Symbol Donut. The new FA-4 donut features a shaded section that sets it apart from the traditional Donut being used with API CK-4.

Visit www.NewDieselOil.com for more information about the new API CK-4 and FA-4 service categories.



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