Shell Lubricants seals new HD engine oil formulations ahead of API CJ-4 sunset

Sources: Shell Oil Co., Houston; American Petroleum Institute, Washington, D.C.; CP staff

Shell Lubricants has timed an ambitious Rotella heavy-duty engine oil portfolio update with two new American Petroleum Institute diesel engine oil standards. Premiering in December, API Service Categories CK-4 and FA-4 succeed Service Category CJ-4 oils widely recommended among on- and off-highway diesel engine manufacturers over the past decade.

Compared to CJ-4 products, which debuted just before major, regulation-driven changes took hold for on- and off-road diesel engines and exhaust treatment systems, CK-4 oils will exhibit improvements in three key areas for engines operating in normal to peak cycles: oxidation stability, owing to newer engines’ tendencies to operate at up to 10°C higher than legacy heavy-duty power; aeration control to curtail entrainment of air in lubricants; and, shear stability, protecting lubricants from being sheared out of grade—i.e., entering the engine as 15W-40 but transforming to 15W-30 toward scheduled drain.

“We have been working on CK-4 and FA-4 oils for more than five years, keeping in mind that meeting the new specifications was simply a starting point for Rotella,” says Shell Lubricants Global Heavy-Duty Diesel Engine Oil Brand Marketing Manager Chris Guerrero. “Our real destination was to create our most technically advanced, hardest working products to date. These oils have been tested over millions of miles and thousands of hours on the road and in the field.”

While CK-4 oils suit most off-road and pre-2016 on-road diesel engines, FA-4 products will be geared to improving fuel economy in on-highway trucks, primarily running 2017 and later engines. The standard describes what API notes are certain lower viscosity oils specifically formulated for select, high-speed, four-stroke cycle diesel engines designed to meet current greenhouse gas emission standards. Along with wear protection features comparable to CK-4 products, FA-4 oils will exhibit additional performance in the face of high temperature, high shear conditions. The category will have limited backwards compatibility, as some older engines are not designed to operate with lower viscosity grades.

Shell Lubricants will effect new packaging of Rotella T4 Triple Protection 15W-30 and 10W-30 plus T5 Synthetic Blend 10W-30 grades—each reformulated with an eye to the CK-4 performance—in August, and plans to transition to new category labeling in December, when API commences CK-4 and FA-4 licensing. T5 Synthetic Blend 15W-40 and T6 Full Synthetic 5W-40 will also be reformulated to meet CK-4 specifications. FA-4-grade Rotella T5 Ultra [Synthetic Blend] 10W-30 and T6 Multi-Vehicle (diesel or gas engine) 5W-30 are likewise forthcoming by year’s end. Both oils will be clearly distinguished in new API Service Symbol “Donuts” accompanying Shell Lubricants packaging.

An open, consensus, five-year-plus development process leading to Service Categories CK-4 and FA-4 was spearheaded by API Lubricants Group, American Chemistry Council and Truck & Engine Manufacturers Association representatives. Shell Lubricants Global OEM Technical Manager Dan Arcy, who chaired the API/ACC/EMA group during its main phase, notes that CK-4 and FA-4 are engineered to address performance requirements and operating conditions of engines complying with sharply reduced nitrogen oxide and particulate matter emissions thresholds attending Environmental Protection Agency 2010 and Tier IV diesel engine guidelines. Both oils will be positioned to contribute to anticipated, 2021–2027 model year targets for on- and on/off-road vehicles, including dumps and mixers, in EPA and National Traffic Highway Safety Administration’s “Phase 2 Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Trucks.”