At least we won’t need new tires come Jan. 1, 2007. Little else, it seems, will emerge unchanged come the New Year. Frames, mufflers, electronics, fuel, engines of course, and more, are being tweaked and tuned to meet EPA’s 2007 low-emissions mandate. Count engine oils in the mix too.

The change is big. Here’s how International Truck and Engine’s fuel and lube specialist Dr. Rodica Barenescu sums it up: “In all my years in engines I don’t recall all these elements changing at the same time. It’s a tall order.”

The engine makers required a new oil formulation to meet the new mandate; specifically, lower levels of sulfated ash, phosphorus, and sulfur, along with new additive packages tolerant of higher temperatures. That new oil category, which comes into effect on October 15, CJ-4, comes with numerical limits on the amounts of these additives in the oil to prevent fouling of the exhaust aftertreatment devices.

The problem is, those very same compounds are what oil makers have used for decades to neutralize acids and prevent wear. “In previous categories, the primary objective was to focus on oil’s contribution to engine durability or maximum engine life,” says Mike Dargento, Chevron’s commercial sector and brand manager for on-highway.

For 2007, there are two new elements in the mix: diesel particulate filters (DPFs) and ultra-low-sulfur diesel fuel. “In 2007,” he says, “in addition to looking at engine durability, we looked at DPF life, as well as the utilization of ULSD, and those two elements became design targets for the oil category.”

The primary goals in creating the CJ-4 category were to sustain emission-control system durability, where particulate filters and other advanced aftertreatment systems are used. “These oils must also be better at handling increased soot levels and heat generated by higher EGR rates present in ’07 EPA compliant diesel engines,” says Jim Putz, Petro-Canada’s category manager, commercial transportation lubricants.

International’s Barenescu says she won’t predict yet whether oil-change intervals will be shortened or lengthened with the new oils. “This won’t be found out now,” she says, “only once it’s been tested in certain applications.”

So, the new oils were designed to withstand higher temperatures, with better oxidation resistance and better deposit prevention, plus better dispersancy to handle higher levels of soot, explains Alex Bolkhovsky, commercial vehicle lubricants technical advisor for ExxonMobil Lubricants.

“And of course, higher heat requires an overall rebalance of the oil to make sure it really performs better in all areas, including wear and detergency. The minute you have higher levels of heat, things tend to degrade faster.”

The oil blenders got a bit of a break with the introduction of ULSD for 2007. While higher EGR rates would force more acids into the oil, there’s less sulfur in the new fuel to begin with (a maximum of 15 ppm of sulfur, compared to today’s 500-ppm levels) that can be transformed into sulfuric acid during the combustion process.

According to Petro-Canada’s Putz, to be DPF-compatible, CJ-4 oil had to meet chemical restrictions not in place for the previous API CI-4 Plus category: 1.0 percent ash; 0.4 percent sulfur; and 0.12 percent phosphorus.

CJ-4 will offer improved wear protection, oxidation,
deposit control, and soot handling, suppliers say

NEW ADDITIVES

The low-ash requirement of CJ-4 posed quite a challenge for the lubricant engineers, and that meant going to entirely different additives. “We’ve had to start looking at more novel and new anti-wear chemistries, detergents, dispersants, which before now were either prototypes or were only used in niche applications,” says Steven Goodier, technology manager for BP Lubricants (Castrol).

It worth pointing out that although the new oils have lower TBN numbers to start with the new additives, they’re said to be able to maintain stable TBN numbers well throughout the drain interval.

“Higher quality base oils (Group II and higher) will now be required to pass the engine sequence tests (new and old tests) and six bench tests set at higher pass limits than the previous category API CI-4 Plus,” Putz points out. “The higher sulfur limit of 0.4 percent also minimizes the possibility of using higher-sulfur Group I base stocks.”

All that to say API CJ-4 really is a different motor oil than we’ve seen before. But will it work in pre-’07 engines?

The short answer? Barenescu says, yes, it will. But it gets complicated.
When the new oil classifications for the 2007 engines were first discussed “there was massive panic in the industry,” recalls Castrol’s Steven Goodier. “People thought there would have to be a compromise between performance and backward compatibility.

“Historically in North America, when new specifications come out on the market, they replace the old ones. With the introduction of CJ-4, you’ll have CI-4 oil still out there, to allow people operating older vehicles to continue to have access to these products.”

“You’ve got 95 percent of the on-highway truck population made up of earlier models,” says Chevron’s Dargento, “and those older vintages don’t necessarily require the CJ-4 formulation. So we’re seeing the market somewhat fragmented for the first time, seeing demand for different formulations in the same sector for the first time.”

The changeover could potentially take several years. As Putz points out, fleets acquiring ’07 engines will be required to stock CJ-4 engine oil, however, this equipment will represent a very small percentage of the overall equipment population in the early stages.

“For fleets not acquiring ’07 engines or owner-operators with legacy engines, they’ll need to conduct a cost benefit analysis to determine whether the performance benefits from CJ-4 and related cost savings outweighs the increased cost of CJ-4 engine oil. I think they’ll see that running CJ-4 engine oil will cost them less in the long run when they factor in savings resulting from reduced maintenance costs, less top-oil, extended engine life, etc,” he says.

Mark Betner, heavy-duty lubricants manager for CITGO, predicts a three-year window where CI-4 Plus oils will still be available. “By 2010, as time goes by and the high-sulfur fuel disappears totally, we’ll be able to evolve back to a one-oil thing.”

Between now and then, fleets planning to use both CI-4 and CJ-4 will need to make room in their storage tanks for the new product. Not much at first, but as more ’07 engines are brought into the fleet the need for bulk storage will be there. Dan Arcy of Shell suggests you start filling with CJ-4 now to purge the old oils from the system. Depending on the capacity of the tank, it could take as many as five fills to render the residual CI-4 product innocuous enough to be used in ’07 service.

“You definitely don’t want a mix here,” he says. “You’ll be plugging DPFs right, left, and center if you aren’t careful.”

At the end of the day, the CJ-4 oils will offer the benefits of improved wear protection, improved oxidation and deposit control, and better soot handling. Yes, they’ll cost more, but you’ll be buying a better oil. Compared with the cost of everything else associated with EPA 2007, CJ-4 oil might seem like a bargain.