This story appears in the June 13 print edition of Equipment & Maintenance Update, a supplement to Transport Topics.
The heavy-duty engine oil specification that has been used for about 10 years is set to be replaced by two new ones: CK-4 and FA-4. The pair have been enhanced to withstand the rigors of lubricating hotter-running diesel engines and boost fuel efficiency better than the current offering, known as CJ-4 and marketed under many brands.
Their ability to resist degrading in higher-temperature engines is the biggest improvement in their makeup compared to CJ-4, experts said.
CJ-4 will be phased out of the supply chain while the two new engine oils are set to go on sale Dec. 1.
For months, manufacturers have used outreach, including websites, to inform the trucking industry of the pending changes in the new specification, which once was known as PC-11.
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“I see a lot of heads bobbing up and down like they understand what’s going on . . . but we won’t know that answer until the December timeframe,” said Dan Arcy, global OEM technical manager for Shell Global Solutions, noting customers won’t see the oils until that time.
One new oil, CK-4, will be backward compatible with existing engines that use CJ-4, but adds new capabilities. Compared with its predecessor, CK-4 will offer enhanced oxidation stability, aeration and shear stability — meaning it resists thickening and is less prone to foaming and breaking apart. The enhancements help the oil retain its viscosity and, as a result, improve fuel efficiency, experts said.
CK-4 will be sold in the same viscosity grades and in the same conventional, full synthetic and synthetic blend oil types.
The other new oil, FA-4, is designed to be used with model year 2017 diesel engines. It will come with the same oxidation stability, aeration and shear stability enhancements found in CK-4. However, FA-4 will be available in lower viscosity grades, which could lead to an additional increase in fuel efficiency.
“I think we have turned a lot skeptics into people who now understand it and are excited by the performance benefits that it brings,” said Shawn Whitacre, Chevron Lubricant’s senior staff engineer.
He said current lubricants made from the CJ-4 specification may be kept around for awhile.
“It is kind of impractical to have an abrupt changeover because of the supply chains that have to run the course,” Whitacre said.
However, most engine manufacturers, as of early May, had not said which oil will be the factory fill in their 2017 engines. And, could the other new oil be used as a service fill if it was not the factory fill? And what about new drain intervals?
“All of those positions are hopefully going to become more clear over the next three or four months,” Whitacre said in April.
Whitacre is chairman of the ASTM Heavy Duty Engine Oil Classification Panel that developed the new oil specifications at the request of the Truck and Engine Manufacturers Association.
Among engine manufacturers, only Navistar International Corp. responded to questions from Equipment & Maintenance Update about its intentions for factory and service fills.
“We have validated FA-4 and that will be an option for our customers with N13 engines,” spokeswoman Lyndi McMillan said. “However, our standard factory fill for 2017 will be CK-4.”
A customer that has CK-4 as factory fill could use FA-4 as the service fill while the reverse is true as well, she added.
As for fleets, they will need to pay closer attention to viscosity grades, said Brian Humphrey, OEM technical liaison, heavy-duty driveline for Petro-Canada Lubricants. Previously, identifying the SAE viscosity grade alone was all that was needed to be done to specify viscosity, he said.
Now, CK-4 and FA-4 change that by adding another “viscometric property difference” called high temperature — high shear to the SAE XW-30 grades, he said.
“This property becomes important in small, high pressure points of the engine and is slightly lower for the FA-4 oils to enable better fuel economy,” Humphrey said. This issue has all the engine makers “conducting lots of internal testing” to ensure which of their engines can use FA-4 oils, he added.
The improvements in engine oil performance are intended to assist engine manufacturers in meeting the next step in Phase 1 of the federal greenhouse-gas emissions rule. The rule mandated an initial reduction of carbon dioxide emissions and improvement in mileage standards by 3%, from a 2010 baseline, by January 2014. That rises another 3% with the upcoming second step in January 2017.
Shell’s Arcy said the key to improved performance is coupling the right base oil with the right additives, such as antioxidants.
“And it could be two or three antioxidants making up the overall chemistry of the oil. We have found there are synergistic effects between them. Putting twice as much X amount of a certain type of antioxidant in might not be as good as if you put in some X and some of Y,” Arcy said, noting there are “a lot of moving pieces.”
Zinc and phosphorus are anti-wear additives used in oils and have antioxidant capabilities.
“So depending on how you balance out your zinc ‘antiwears,’ it’s going to also influence what is the best antioxidant to use and how much you need,” he said.
PC-11 is “the most stringent standard ever. You never shed requirements, you only add to them,” Whitacre said, referring to earlier work done to develop CJ-4, once known as PC-10.
There are nine engine tests that lubricant manufacturers have to run, and two of them were added to get to CK-4 and FA-4, Whitacre said. Seven were a part of the CJ-4 category that requires engine oils to stand up to high operating temperatures for 360 hours in a running engine.
The oil pan, or sump, temperature has risen already to 115 degrees Celsius from 105 degrees Celsius, as engine manufacturers “have tried to squeeze a little more fuel economy out” with existing CJ-4 oil, Humphrey said.
Engine makers will probably allow the oil pan temperature to go up another 10 degrees to 125 degrees Celsius as they strive for more gains in fuel efficiency, he said.
Arcy suggested that not every new engine will be 10 degrees hotter, however. “One might be 10 degrees, one could be 2 degrees, one could be 5 degrees or no hotter.”
Meanwhile, selective fleet testing of the new lubricants remains under way.
“We have been hearing that some fleets already have been taking progressive steps and testing the lower viscosity FA-4 oils to get that [extra] fuel efficiency benefit,” said Randy Tumbarello, U.S. fleet director at Trimac Transportation Inc., whose parent company Trimac Group that ranks No. 45 on the Transport Topics Top 100 list of the largest U.S. and Canadian for-hire carriers. He also is chairman of the engine study group at American Trucking Associations’ Technology & Maintenance Council.
Arcy said Shell has worked with several on-highway fleets “that put on high mileage, 250,000 to 300,000 a year [per truck].”
Shell began testing its low viscosity FA-4 type oils in 2012 and has accumulated more than 30 million miles of testing with every engine manufacturers’ on-highway product, he said. Some engines have been run out to 900,000 miles, with inspections along the way.
Some owner-operators and fleets with older equipment may see only a small change switching their CJ-4 oils to the enhanced CK-4 oils. Other fleets with a combination of older and newer equipment may choose to stock both CK-4 and FA-4 oils until the older units are cycled out of the fleet, according a statement from Exxon Mobil.
Filter manufacturers also have explained there should be no adverse effects on the filters currently in use, Tumbarello said, describing comments these manufacturers made during a recent TMC discussion of the pending changeover.
Engine manufacturers have said that, at a minimum, they wanted to maintain drain intervals, Arcy said. “I think we have to wait for the OEMs to give their recommendations.”