'07 Oils: How Good?

Nov. 1, 2005
You win one hand. And you may win two more. Or at least not lose big on either. That's the spot lubricant suppliers find themselves in as the EPA '07 emissions mandate draws closer. While confident the motor oil being developed for '07 engines will be backward-compatible for earlier engines, lubricant engineers at this point are hedging their bets on where drain intervals will wind up when the oil

You win one hand. And you may win two more. Or at least not lose big on either. That's the spot lubricant suppliers find themselves in as the EPA '07 emissions mandate draws closer.

While confident the motor oil being developed for '07 engines will be backward-compatible for earlier engines, lubricant engineers at this point are hedging their bets on where drain intervals will wind up when the “new” oil is used in '07 as well as in pre-'07 engines.

Backward compatibility itself is good news, of course, because it means fleets will be able to use the new Proposed Category 10 (PC-10) oils in their pre-'07 trucks without fear of reduced protection from wear, corrosion or piston deposits.

Indeed, when it comes to pre-'07 engines, Mike Lynskey, heavy-duty engine oil technology manager for Castrol Lubricants, reflects the feelings of most lubricant makers: “We're very happy with our [PC-10] oil performance in older engines in testing so far…[and we now have] six to nine months worth of time to hone our formulas.”

“Our main concern going forward is how the oil will behave in '07 engines because we're not sure if we've seen the final configuration of '07 engines yet,” adds Lynskey. “We're still not 100% sure what the final changes in engine operating temperature will be.”


While performance, as always, remains the watchword, extended drain intervals for pre-'07 engines could be redefined. The strict chemical limits and testing requirements placed on PC-10 oils to ensure they will meet the needs of '07 engines, particularly maximizing DPF cleaning intervals, may mean — at least initially — pulling extended drain intervals back to original, OE-recommended levels.

“The reason for this is that we're going through a paradigm shift when it comes to the chemical formulation of engine oils for 2007,” explains Jim McGeehan, global manager of engine oil technology for Chevron Products Co., and chairman of ASTM's Heavy-Duty Engine Oil Classification Panel, the industry group that develops oil category criteria.

“In every previous generation of oils, we've never had a situation where we've needed to put in place chemical limits on our formulations,” he continues. “With PC-10 oil, however, we've had to form a ‘chemical box’ in order to protect sensitive aftertreatment components from damage — namely, diesel particulate filters (DPFs). That has changed the oil composition substantially.”

That chemical box means the sulfur content of the new oil must drop to 0.4%; phosphorous to 0.128%; ash formation to 1.0%; and oil volatility to 13%.

The biggest area of uncertainty is the reduction of PC-10's total base number (TBN) to a level of 8 or 9, down from the TBN range of 11 to 13 found in today's truck engine oils. That drop-off in base reserve may — and lubricant manufacturers emphasize the word may here — lead to more conservative oil drain intervals.

“The lower TBN changes things,” says Reginald Dias, director of commercial products for ConocoPhillips. “Lower base reserve means less acid neutralization capability, and that means the oil just can't last as long.”

There is a caveat, however. The introduction of ultra-low-sulfur diesel fuel (ULSD) in 2006, which will have a sulfur content of only 15 parts per million (ppm), could help make up for the lower TBN in PC-10 oils. “ULSD is the key factor. Less sulfur in the fuel means production of [fewer] acids in the engine and that's a positive for [PC-10] oil life,” explains Dias.

Mark Betner, manager of heavy-duty products for Citgo Petroleum, agrees. “As long as we take sulfur out of the mix, we'll be OK,” he says. “I don't think we'll see a rollback of oil drain intervals below what I call a ‘normal’ range.

“But fleets using extended drain intervals really need to dial it back and watch [PC-10] oils using an oil analysis program,” Betner cautions. “If you are outside the envelope — beyond 35,000-mile drains — you'll be outside the engine builder's recommendations. But if you are between 15,000 and 35,000 miles on drain intervals, not much should change.”


Chevron's McGeehan concurs, adding that lubricant manufacturers are targeting a PC-10 oil drain interval of 25,000 miles. “The range of oil drains in the U.S. trucking market is so large — from 15,000 to 60,000 miles — that we can't make a recommendation on drain points as of yet,” he says. “By taking the sulfur out of the fuel, the oil should last longer. As long as the CI-4 oils used today? We don't know that yet.”

“Our primary goal from the start of PC-10 testing is to maintain equipment durability,” adds Alex Bolkhovsky, commercial vehicle technical adviser for ExxonMobil. “In the end, it's all a balance. When in doubt, we want to err on the conservative side.

“That's why we're telling customers to initially stick with engine OEM oil drain recommendations, even though the PC-10 oils are going to be so heavily validated,” he says. “We just don't want them put in a position where their warranties could be voided.”

Ironically, when PC-10 oils are used in '07 engines, they could lose the benefit of the ULSD boost. “We know that for '07 models we'll see an increase in operating temperatures,” says Conoco's Dias. “Those higher temperatures represent a significant question mark for us. We don't know what will happen to PC-10 oil life under higher temperature loads.”

The use of exhaust gas recirculation [EGR] is also going to double in '07 engines, increasing the amount of soot levels PC-10s must handle, adds Citgo's Betner.

“The good news is that “we don't need as much detergent in the oil to handle sulfur levels,” he explains. “The bad news is soot levels are going to go up, along with engine operating temperatures. That's every bit as challenging an operating environment as handling high sulfur levels.”

“The addition of a DPF and double the rate of EGR is going to put a lot more additional load on '07 engines,” notes Chevron's McGeehan. “As a result, we're going to see spikes in both oil and coolant temperatures.

“So the main litmus tests when we get to '07 engines with PC-10 oils is, can they resist heat and can they protect the engine? At this point, we know they will be able to do both. The only question is where the drain interval will be,” McGeehan explains.

This is a gray area for lubricant makers because they haven't done enough real-world testing of PC-10 oils in '07 engines to see how they behave.

“The engine manufacturers are still being secretive about the direction they are taking for '07,” says Betner. “We know generally what technological path they are using but it's the nuances that come out of real-world experience that we don't have enough data on yet.”

“Will we be able to foresee every twist and turn in conditions PC-10 oils might face? The answer is no,” he continues. “But will we be able to lubricate and protect the engines well? That's an absolute yes.”


While lubricant manufacturers don't know exactly what PC-10 oils will cost, they do know they're more expensive to develop than the CI-4 oils on today's shelves. This is primarily because the testing requirements to certify PC-10 oils for the market are so high.

“Here's a little history,” says Citgo's Betner. “Back in 1971, an oil had to pass three tests to receive API [American Petroleum Institute] certification, at a cost of about $1.5 million.

“By 2002, however, to license an oil for the CI-4 standard it had to pass 16 tests at a cost of $16 million,” he notes. “And this is just for one formula of CI-4 oil. If you want to offer a CI-4 premium grade, you must go through all those tests and spend that $16 million again, whether [the formula] passes the test or not.”

For 2007 the stakes go up even higher, as PC-10 oils may have to pass between 24 and 25 tests, at a cost of $25 million, says Betner.

“The industry is going to spend tens of millions just to test these new oils,” adds Dan Arcy, technical product marketing manager for Shell Lubricants.

“Conducting just the Caterpillar C-13 test is going to cost $120,000 and require 500 hours,” he says. “But one of the biggest positive factors is that we have more testing time this go-round compared to what we went through for CI-4 engine oil development for 2002.”

All of this testing has made oil suppliers confident that their PC-10 products will easily protect current and '07 engines.

“The beauty for the consumer is that there won't be any disparity in protection against wear, corrosion, etc. like we had with a lot of 1971-era oils,” says Betner. “These oils won't be shots in the dark. They'll have a lot of integrity in terms of performance expectations.”

“Fleets can be very confident in the capabilities of PC-10 oil, which is most likely going to be called CJ-4,” says Arcy. “We've had much more development and testing time.”

Yet all that testing and reformulation makes it difficult to predict what the cost will be to fleets, says ExxonMobil's Bolkhovsky.

“We have of all this testing we need to do and we are putting new additives into the oil; quite a number of novel additives we've never produced before,” he explains. “Also, the scale of production down the road, i.e., how much of this oil the market actually buys, is also going to affect pricing.”


Most lubricant makers expect initial demand for the PC-10 oils to be low, as '07 engines gradually work their way into the industry. As a result, supplies of CI-4 and other pre-'07 engine oils won't dry up anytime soon.

“The rollout of '07 engines is going to take place slowly, so as a result, demand for PC-10 oil will be slow for the first part of 2007 at least,” notes Conoco's Dias. “That's why we expect demand for CI-4 oils to stay high through 2007 and beyond, and why we'll need to keep making it in significant quantities.”

About the Author

Sean Kilcarr | Editor in Chief

Sean previously reported and commented on trends affecting the many different strata of the trucking industry. Also be sure to visit Sean's blog Trucks at Work where he offers analysis on a variety of different topics inside the trucking industry.

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