When the new oil classifications for the 2007 engines were first discussed – and similar restrictions for European oils – "there was massive panic in the industry," recalls Steven Goodier, technology manager for BP Lubricants. "People thought there would have to be a compromise" between performance and backward compatibility.

The new CJ-4 oil category, which will go into effect Oct. 15 and is a must for 2007 engines, has some major differences from previous heavy-duty engine oil categories.

"In previous categories, the primary objective was to focus on oil's contribution to engine durability or maximum engine life," says Mike Dargento, Chevron commercial sector and brand manager for on-highway. For 2007, there are two new elements in the mix: diesel particulate filters and ultra-low-sulfur diesel fuel. "In 2007, 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."

Ultra-low-sulfur diesel fuel, or ULSD, will have a maximum of 15 ppm of sulfur, compared to today's 500-ppm levels. Federal regulations call for this fuel to be in place at retailers by Oct. 15. It's required for 2007 engines, and chances are it will replace the higher sulfur fuel at most fueling locations.

Diesel particulate filters, as explained elsewhere in this issue, will be used on all 2007 engines, and most will have diesel oxidation catalysts as well.

Because of these aftertreatment devices, for the first time the oil category contains numerical limits on the amounts of certain chemicals in the oil: sulfated ash, phosphorus and sulfur. The oil companies use the acronym SAPS, and call these low-SAPS oils. These compounds must be kept to a minimum because they can foul the aftertreatment devices.

The problem is, those very same compounds are what oil makers have used for decades to do things such as neutralizing acids and preventing wear. This meant going to entirely new additives.

"Some people have used the phrase paradigm shift," says Mark Betner, heavy-duty lubricants manager for CITGO.


"The new oil category has two distinct areas it's looking to enhance lubrication," explains Alex Bolkhovsky, commercial vehicle lubricants technical advisor for ExxonMobil Lubricants: improved performance attributes, and compatibility with aftertreatment devices.

"The big thing from an environment perspective is that exhaust gas recirculation will be increased, close to double," he says. "What increasing EGR does is make the engine environment a bit harsher. You're adding heat, higher levels of soot. Normally you'd be adding higher levels of acid as well, but we get the benefit of ULSD in 2007, so that will counteract the levels of sulfur that form an acid in the engine."

So the new oils have been designed to withstand higher temperatures, with better oxidation resistance and better deposit prevention, plus better dispersancy to handle higher levels of soot, Bolkhovsky says. "And of course, higher heat requires an overall rebalance of the oil to make sure they really perform better in all areas, including wear and detergency. The minute you have higher levels of heat, things tend to degrade faster."

All this had to be done without using the conventional SAPS additives the industry has used for decades.

Bolkhovsky compares the challenge to food: "It's like saying, 'This pizza tastes great, but I want a low-fat pizza that tastes even better.' That's what we had to do – design an oil with fewer conventional components that worked even better."

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 BP's Goodier.

For instance, sulfated ash has traditionally been used to neutralize acids. This ability is measured by a TBN number. "Under traditional chemistry, lower ash means lower TBN," says Dan Arcy, technical marketing manager for Shell Lubricants. At the same time, higher EGR means more acids in the oil. Fortunately, the ultra low sulfur diesel will help counteract this, with less sulfur that can be transformed into sulfuric acid during the combustion process.

"We're not going to have as much stress on the oil's 'Alka-Seltzer' system," Betner says. "We're not wiping out the TBN, just reducing it to a level that's tolerable for that [diesel particulate] filter." CI-4 oils have about 11 to 13 percent; CJ-4 will have 9 to 10 percent, he says.

Bolkhovsky also points out that although the new oils have lower TBN numbers to start with, with the new additives, "we developed them to be able to maintain that level well throughout the drain interval."

One factor that helped in the development of CJ-4 oils was that Europe went to low-SAPS lubricants a year earlier, giving most oil makers some experience with these new additives.


So we know why CJ-4 oils are needed for the 2007 engines. But what if you aren't planning to buy the new engines for a few years?

Backward compatibility "is something that the industry had an eye on right from the beginning," Bolkhovsky says. "Because of the performance requirements these oils will have, we feel pretty confident we will have backward compatibility."

Although the new oils should be backward-compatible with pre-2007 engines, at least in on-highway applications, it looks like CI-4 oils will continue to be available alongside the new CJ-4 formulation. This is a departure from previous category changes, where the old formulation pretty much went away after a transition period.

"Historically in North America, when new specifications come out on the market, they replace the old one," Goodier says. "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."

There are several reasons fleets might want to continue buying CI-4 oils for their pre-2007 equipment. One, the new oils may be more expensive. Two, they might not work as well in some severe-duty applications. Three, they might not allow oil drain intervals to be extended as much as some fleets are doing today.

"You've got 95 percent of the on-highway truck population made up of earlier models," says 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."

CITGO's Betner says while the new oils should be backward-compatible in most cases, he can't say for sure whether using them provides advantage to users of older engines. That's a change from the last time we had a new oil category.

"Because we had to address more severe conditions with the 2002 oil (CI-4), my feeling was it would behave quite nicely and offer advantages in older engines. But I think when we use the term paradigm shift, I can't say for sure [the new oils] will be an improvement for older engines. I've got presentations where we showed clear improvement of deposit control with the 2002 CI-4; I don't see where we can necessarily say that today."

While he says he believes after testing is finished, the oil industry will "feel very comfortable with CJ-4 technology," Betner says he doesn't think it's superior in every situation. For instance, in off-road applications that are still using the higher-sulfur diesel fuel, users might do better with the CI-4 oils.

Another scenario where a fleet might want to stick with the current oils is in the case of extended drain intervals.

"Honestly, we don't have data on that," Betner says. "Don't just assume that because CJ-4 is backward compatible and normal drains don't look like they're going to be modified" that your extended drains will remain the same. "If you're doing a 50,000-mile drain, you should definitely use oil analysis and re-establish a baseline" when you go to the new oils.

Betner 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."

Oil makers along with engine manufacturers and others are field-testing the new engines and the new oils in a variety of configurations. They're testing the new oils in current engines with ULSD, testing them in 2007 engines with ULSD, and testing them in engines with regular diesel fuel.

"We've had more time to test this time," says Shell's Arcy. "Last time we were rushed."

For instance, ExxonMobil has accumulated 7 million miles of testing on its CJ-4 candidate oils. "In field testing, on-the-road experience, we've had some very positive results using both the ULSD and the 500-ppm diesel that's currently around," Bolkhovsky says.


Not only are the 2007 engines going to be more expensive, but the new fuels and lubes required will likely cost more, too.

Because of the new chemistries, these new oils will be more expensive to make. Many oil companies predict that these costs will be at least partially passed on to the end user.

"It is extremely likely that there will be an increase in cost to the consumer," Goodier says. He notes there may be a short-term bump because the additives being used in the new oils have not been produced in massive quantities in the past, having been used mostly in niche products.

The new additives aren't the only factor in price.

"Since 1970, we have gone from about a $1 million to $2 million testing/licensing process to over $30 million to get this product ready for 2007," Betner says. That compares to about $15 million to $18 million last time around, for 2002, he says. "Logic tells you CJ-4 technology will cost more because of that. But I can't say how much, or even 100 percent if they'll go up."

Chevron's Dargento says he has seen estimates that the new oils will cost 10 percent to 30 percent more than the current CI-4 Plus formulation. But oil makers say the market will ultimately determine the price.

Oil makers say although the new oil may be more expensive, you're also getting more in return.

"This is a major change," says BP's Goodier. "It's not just a tweak to the formulation, and there is the potential to start from scratch, which will actually be superior to what we have today. In which case, the increase in cost will hopefully be justified by the increase in performance." Extended engine life, reduced wear, reduced fuel consumption, and so forth, he says, have the potential to offer real, tangible benefits to the bottom line.

"Even though we had some limits put on us, we actually have a better product," says Shell's Arcy. He says the new oils will have better oxidation control, better wear protection and better soot handling.

Dargento points out that in uncertain times like these, it's also a good idea to look beyond the lubricants themselves and choose a supplier that can also provide information and education. "There are dozens of unanswered questions on the mind of everyone that operates a truck, whether a large fleet or one or two units."