In a highly competitive business where every penny-per-mile in costs adds up quickly, truckers now demand better and better fuel efficiency. And beginning with model-year 2017 heavy-duty trucks, federal regulators will as well. So for the first time in 10 years, OEMs, oil marketers, and standards organizations are coming out with a new category for heavy-duty diesel engine lubricants designed to maximize fuel efficiency from the latest in powertrain technology.

The catch is this new category actually will include two lubricant standards, and it will be up to the end users—truck operators and shop personnel—to know and to use the correct engine oil for a variety of equipment. But that decision might not be as simple as just following the engine makers’ recommendations.

And that’s what has everyone’s attention.

The good news, as this edition of American Trucker goes to press, is that the involved parties are expected to have settled the performance details and testing procedures, and the official ballots are circulating with the aim of a year-end final approval. It will be another 12 months before the current product category, CJ-4, will be phased out.

In the meantime, engine oil producers will be perfecting their formulations, testing labs will have their heavy-duty engines humming 24/7, and, ultimately, engine makers will set their official recommendations. That’s essentially not much different from previous new-spec cycles.

What’s different this time around is that the latest generation of engines—designed for low-rpm “downspeeding,” among other high-tech touches to maximize fuel efficiency and limit emissions—run hot. To get every last fraction of mpg out of them requires a lubricant with lower viscosity and even a different way for consumers to consider viscosity called high-temperature/high-shear, or HTHS. Oil marketers, based on tests of preapproval formulations, report low-HTHS lubricants provide a 2 to 3% improvement in highway fuel economy.

For truck operators with older equipment, however, this PC-11B subcategory, to be named FA-4, likely will not be the best option. For those older diesels—certainly pre-EPA ’07 models and perhaps even EPA ’10—the new PC-11A standard, CK-4, will be an improved version of, and direct replacement for, the outgoing CJ-4.

So far, so good. But an anticipated uncertainty in the marketplace will center first on which lubricants the engine manufacturers will recommend and, second, on maintenance shop management. Will a company with both old and new equipment go along with a double-lubricant standard, at least for several years’ worth of drainage intervals as the older trucks are replaced? Or will they opt to sacrifice some of the performance benefits of FA-4 to keep the engine oil inventory simple?

This round of new engine oil standards began with a request from the Truck & Engine Manufacturers Assn. (EMA) and its members, explains Roger Gault, EMA vice president for regulatory activities.

Specifically, the CK-4 formulation is intended to be “fully backward-compatible,” meet enhanced oxidation requirements, and provide some benefit in aeration control. Essentially, CK-4 will be a new and much improved evolution of the tried-and-true CJ designation.
FA-4, however, is “a different animal,” Gault points out. The engine makers wanted a standard that will bring lower HTHS oils into the heavy-duty market.

Previously, whether in 10W-30 or 5W-30 HD oil, the HTHS measure has been 3.5, and CK-4 will retain that baseline. The FA-4 standard will allow HTHS to go as low as 2.9, but that’s still in line with the lower limit of the SAE 30 grade.

“It’s kind of confusing in the marketplace because we’re going to end up with 5W-30s or 10W-30s that fall into both categories and they’re going to be different,” Gault adds. “This is new territory for us. Historically, all the heavy-duty diesel engine oils have been in the higher HTHS category. Part of the consumer education process that the industry will be undertaking is to help them understand that there are multiple oils that would carry the same viscosity grade.”

On the user side, EMA expects the traditional transition discussions around which oil spec applies to which truck make and model. “That’s a challenge every time we change a category, but even more so this time,” Gault says, referring to how far back the compatibility will go. “There’s no simple answer, unfortunately.”