Engine Makers, Fleets Prep for New Heavy-Duty Engine Oil Rollout
PC-12 Oils Promise Fuel Savings, Better Protection Against Engine Wear
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As the trucking industry moves toward the next generation of diesel engines, the introduction of new oils designed to further enhance fuel efficiency also is on the horizon.
The upcoming PC-12 heavy-duty engine oil category is on track to reach the end of its three-year development and testing journey in December, with the commercial release of these oils targeted for January 2027.
Dennis Bachelder, senior engineer for engine oil licensing and certification at the American Petroleum Institute, said 2026 will be a mandatory waiting period while oil and additive companies complete their development of products for the marketplace.
The API has been developing the oil in partnership with its oil company members, the Truck and Engine Manufacturers Association and the American Chemistry Council.
“PC-12” stands for “Proposed Category 12,” as this is the 12th oil category the API has developed. PC-12 provides better fuel economy through friction modifiers and through lower viscosities for weights potentially as low as 0W-20. It also can offer better protection against increases in viscosity due to oxidation. A detergent will prevent carbon buildup, while a dispersant will keep solid carbon material suspended in the engine oil. This will prevent sludge from gathering at the bottom of the crankcase, from where it could be sucked up by the oil pump and returned to the engine.
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PC-12 development began several years ago as an effort to produce oils that would match the requirements of 2027 model year engines. Manufacturers had designed those engines to comply with the Environmental Protection Agency’s Greenhouse Gas Phase 3 standards set to go into effect that year, but EPA Administrator Lee Zeldin on July 29 announced a plan to overturn the “endangerment finding” that underpins the rule — casting serious doubt on the future of the regulation.
Regardless, PC-12 will quickly become standard on shelves and in service centers, Bachelder said.
“The investment’s been made,” he said. “Like many things, these are long lead times, and even if this emission standard is not required, the modern engines will still benefit from the performance of the engine oils we are developing.”
PC-12 will be the first new heavy-duty engine oil category since the CK-4 and FA-4 categories were introduced in 2017. Those oils offered a lower-viscosity formulation and were a better fit for 10W-30 weight oils that can be used by newer engines and that offer improved fuel economy. The FA-4’s thinner formulation is designed to match the tighter tolerances in newer engines that provide for better fuel economy and reduced greenhouse gas emissions. However, it’s not backward compatible with older truck engines, which instead require a CK-4 formulation.
The new oil won’t be known as “PC-12” when it reaches the market. Instead, it will be released in two service categories. One will be FB-4 for lower-viscosity weights, such as 10W-30 and below. It will be backward compatible for newer engines designed to use FA-4 engine oils. The other will be CL-4, which will be backward compatible with older engines in mixed-truck fleets. It will be used for higher viscosities, such as 15W-40, as well as 10W-30.
Older API service categories will remain available. In fact, the oldest oil still available domestically, CH-4, was created in 1998.
Industry Feedback
Today, many trucking businesses operate a mix of vehicle models and use 15W-40 and CK-4 oils for all their trucks, lest an incompatible oil be inadvertently poured into an older engine.
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Robert Braswell, executive director of ’ , said the industry has been migrating slowly to lower-viscosity oils, but 15W-40 remains the most popular choice. Newer engines are designed with 10W-30 in mind and were likely factory-filled with it.
“The older engines before 2017, 15W-40 is what it was made for, so that’s probably where you want to go,” he said.
Over time, Braswell expects more fleets to use the lower-viscosity oils because of the improved fuel economy and extended oil drain intervals. Some fleets say they see a 1%-2% improvement in fuel economy. Others say there’s no difference. If an engine was designed for FA-4, then fleets may want to use it because of the warranty.
“I think as time goes on, you’re going to see more and more usage of the lower-viscosity oils because the fleets that are using them generally say they’re having good success with it,” he said.
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Truckload carrier Nussbaum is working with an oil supplier that has a PC-12-compliant oil in the works, said James Grier, director of fleet service. The company tries to use 10W-30, FA-4 rated oil for all its 600 company-owned trucks, although it sometimes isn’t available from an over-the-road service vendor. The fleet operates on a six-year trading cycle, with its average truck being 2.74 years old.
Grier said Nussbaum has seen significant improvements with FA-4 over its CK-4 counterpart. There’s still life left in the oil at the 75,000-mile oil service interval. The company was discussing pushing intervals to 90,000 miles, but the coming PC-12 category has put that discussion on the back burner.
Grier is confident Nussbaum will run a PC-12 oil after it is released into the market. It will stock one oil at all its locations and will have conversations with vendors about which oils they are carrying.
“We trust the FA-4,” he said. “Now we’ve got to get the trust in the PC-12.”
Old Dominion is making a fleetwide switch from the 15W-40 oilsit has been running for many years to a 10W-30 synthetic brand. (Old Dominion Freight Line)
Meanwhile, less-than-truckload hauler Old Dominion Freight Line is making a fleetwide switch from the 15W-40 oils it has been running for many years to a 10W-30 synthetic brand in the same family. All of its 11,000 company-owned trucks will use the same oil serviced by shops across its network.
Dan Bennett, vice president of equipment and maintenance, said the carrier will convert one location to the new oil for a while before making a systemwide change. Switching oils is a challenging project, he said, but it’s worth it.
“It could be as much as 4%,” Bennett said of the fuel savings. “I would be happy with 1% to 2%.”
Although the market will change in a couple of years with the PC-12 products, the lower-viscosity oil on the market today offers too many advantages to wait, he added.
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“When you’re doing math on 11,000 trucks, the numbers get big very quickly, [so] that two years is a long time to shelve it,” Bennett said.
ODFL ranks No. 9 on the Transport Topics Top 100 list of the largest for-hire carriers in North America.
Truck leasing and transportation giant Penske uses one type of oil across most of the trucks in its diverse fleet of roughly 409,000 units, said Chris Hough, vice president of maintenance design and engineering. All 2008 engines and newer use a CK-4, 10W-30 oil.
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“Our No. 1 goal is customer satisfaction, customer uptime, so we’ll never sacrifice that,” he said. “But again, for the simplicity piece of it, and the fact that there’s really not a lot to be gained by having two oils in a shop, it’s not worth it.”
The company does have a small number of older engines that use 15W-40. Where needed, it’s stored in clearly labeled 55-gallon drums.
Hough said Penske will use the new PC-12 oil as long as it is backward compatible. It’s looking for an oil that will be a better lubricant with slightly better fuel mileage and better intervals so that Penske can maximize the oil’s life.
Penske Logistics ranks No. 12 on the for-hire TT100 and No. 19 on the TT Top 100 logistics companies list.
LTL carrier ABF Freight also utilizes CK-4 motor oil and has used 10W-30 across its entire fleet for all vehicle classes for several years, a company spokesperson said. ABF said standardization “simplifies maintenance and supports operational efficiency.” Its move to 10W-30 resulted in fuel economy improvements measuring under 2% in a dedicated lane test, with no other results observed.
The fleet is looking closely to see what happens with PC-12, with its priority remaining to use a single, standardized oil compatible with all existing equipment and factory fills.
ABF’s parent company, ArcBest, ranks No. 13 on for-hire TT100 and No. 44 on the logistics TT100.
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Most of NationaLease’s 104 member companies likewise want to standardize oils and limit their inventories, said Joe Puff, vice president of truck technology and maintenance.
He expects many fleets will be reluctant to adopt the PC-12 oil out of fears it won’t be backward compatible, just as fleets have been slow to transition from 15W-40 to 10W-30. They’ll want to see how successful progressive fleets have done it. He would be concerned about switching a 2016-or-older engine to PC-12. Once PC-12 comes out, original equipment manufacturers will inform the industry about backward compatibility.
“I think most people will do what they have to for their 2027 engine,” he said. “But they’re not going to, I don’t think, jump on the bandwagon to use that oil for their older engines, again, unless the OEMs endorse it. Still a lot of questions out there.”
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