The marketplace is full of oils for natural gas, diesel and passenger car or gasoline engines. But what if those oils could be combined into one product and used across all fuel sources? This month, Shell Rotella released Shell Rotella T4 NG Plus, available in 15W-40 viscosity grade.
The new oil covers all medium to heavy-duty Class 8 trucks. "Rotella T4 NG Plus is designed and optimized for natural gas engines and also meets the requirements for diesel engines, as well as API SN requirements for gasoline-powered engines," says Dan Arcy, Shell Rotella Global OEM Technical manager and Industry Trade Association liaison.
API (American Petroleum Institute) SN oils are the service classification for passenger car engine oil. Shell's current product, Rotella T5 NG, will be discontinued.
Industry changes
Industry changes for natural gas prompted the company to develop the new engine oil. Reducing potential misapplication and the need for extra tanks by combining the oils into one product was another motivator.
Cummins-Westport, one of the major engine suppliers of natural gas-powered engines for the mobile market or the transport market, introduced a new mobile natural gas engine oil performance specification, the Cummins Engineering Standard (CES) 20092 in 2018.
The specification, introduced for stoichiometric combustion Cummins Westport mid-range and heavy-duty engines, provides improved oxidation and thermal stability compared to former natural gas oils.
"Natural gas engines can have peak temperatures higher than diesel, so you have to design an oil that's going to handle those higher temperatures," Arcy says.
Oil drain intervals
The specification, depending on the application in which the engine is used, also provides for a decrease in oil drain intervals. "For some of the engines running in, let's say, bus-type applications, the oil drain interval is going from 500 hours up to 1,000 hours. This is a significant improvement in oil drain interval versus the prior spec, which was Cummins CES 20085. For highway, and again, depending on the load and application, we're going from 25,000-mile drain intervals to 40,000-mile drain intervals," Arcy says.
"This is a significant improvement in product performance but also in savings for the customer in service intervals for their applications."
Oxidation, nitrate control
Other changes include oxidation and nitrate control. "Nitration is a concern with natural gas," Arcy says. "Nitration happens at higher temperatures and these engines run at higher temperatures.
"So, this product, along with improved oxidation and nitration control, has a very high total base number or upload reserve so you can go long drain intervals with it. We also meet API CK-4 performance standard with this product, so it can be used in any application calling for API CK-4, API SN, for passenger car, along with meeting Cummins 20086."
Like API SN, API CK-4 is an engine oil category. API CK-4 oils, released in December 2016, have improved oxidation resistance, shear stability and aeration control.
Arcy notes, because older engines, also known as lean-burn engines, run a different air-fuel ratio, they require an oil that has a low ash level and meets the Cummins CES 20074 specifications.
"This is important because CES 20074 and CES 20092 have different specifications. It's impossible to have one oil that meets both of those specifications."
Upcoming
New in 2020, is the upgrade relaunch of Shell Rotella T6 full synthetic, 0W-40. "A change from our previous CJ-4 oil products, we've enhanced the oxidation to meet API CK-4, along with maintaining the strong characteristics for piston deposit control for cleanliness and for wear protection," Arcy says. "Because it's 0W-40, it does meet those low-temperature requirements, but it also has extreme protection for high temperatures as a result of being a synthetic."
The OW-40 also meets the Ford specification for diesel pickups. A common question diesel pickup owners ask Arcy this time of year, is if they can switch from a synthetic oil to a mineral?
"There is no issue changing from a 15W-40 to a 0W-40. That's fully acceptable," he says.
Not only are there no negative consequences, Arcy says there are benefits to switching. "Going into the 0W-40 in the winter is going to give you better starting capabilities than you'll have with 15W-40. The engine will turn over a lot easier, and easier in the summer as well, but it's not as pronounced. But in the winter, you'll definitely see a difference."
For more information about these Shell Rotella engine oils, visit Rotella.com.