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Synthetic Lubes

The switch to synthetic lubricants can result in many benefits.

April 2008, TruckingInfo.com - Feature

by Deborah Lockridge, Senior Managing Editor

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Reimer Foundations in Valleyview, Alberta, Canada, is a sand, gravel and concrete mixing and transportation company that runs nine gravel trucks, 14 mixers and a team of loaders and backhoes six days a week, 13 hours a day, year round. Temperatures range from 30 below in the winter to 100 degrees in the summer. And the machines are also mixing, loading and transporting very heavy loads - for instance, their gravel trucks transport payloads weighing in at 121,000 pounds.

The big temperature range and heavy use made the company a good candidate for synthetic lubricants. So Reimer started using synthetic lubes from Petro-Canada for the rear ends and final drives, as well as Duron synthetic 5W-40 engine oil.

Fleet manager Randy Bond says since they made the switch, they've had less downtime, extended oil drain intervals from 300 to 500 hours on the engine oil and doubled service intervals on their rear ends.

"We're getting really good performance out of our oil," Bond says. "For example, one of our trucks has about 1.4 million kilometers (approximately 870,000 miles) on it, and there is absolutely nothing wrong with it, and it requires very little top-up." While there are many factors that have contributed to the truck's long life, he says, he feels that one of the biggest ones is the synthetic 5W-40 engine oil.

Synthetic lubes have become accepted in transmissions and rear axles as a way to extend drain intervals as well as warranties and help improve fuel economy.


However, acceptance of synthetic motor oils in the trucking business has lagged behind the automotive world or Europe's trucking industry, because they cost two to three times as much as mineral-based oils. But with fuel prices at $4 a gallon, the potential fuel savings of using synthetic oils could change that.

Synthetic Benefits

Yeong Kwon, commercial vehicle lubricants technical advisor for ExxonMobil, says you can summarize the benefits of synthetic lubricants in four ways:

1. Synthetic oil tends to have a higher viscosity index, meaning it remains thick at high temperatures and light at low temperatures. This in turn leads to easier cold starts and longer component life. Related to this, he says, is that because synthetics are made of molecules that chemists design, the chemists can create base stocks with the ability to maintain stronger and thicker lubricating films, and that imparts wear protection even before the additives come into the picture.

2. A lower traction coefficient means less friction and heat, which promotes energy efficiency and fuel economy.

3. Improved oxidation and thermal stability means the oil is less likely to thicken with age and offers better deposit control. This is what makes synthetics a good bet to help extend oil drain intervals.

4. Lower volatility means less oil loss and therefore there's less makeup oil needed.

Because of these properties, synthetic motor oils offer excellent cold-weather starting abilities, better wear protection (especially in severe applications and high loads), resistance to oxidation at high operating temperatures, and, at least in the lab, improved fuel economy.

Perhaps one of the main reasons fleets have turned to synthetic motor oils is that they are a valuable tool to help extend oil drain intervals.

Arkansas-based P.A.M. Transportation has extensive experience with using synthetic motor oils to go 150,000 miles between drain intervals, working closely with their oil supplier. "We've had a billion miles of experience with that - that's five round trips around the sun," says Carl Tapp, P.A.M.'s vice president of maintenance.

While his fleet did not see a noticeable fuel economy improvement using synthetics in the engine, rear ends and transmissions, "we did see increased starter motor and battery life, because the engines were turning easier. And a soft-dollar benefit may have been in improved truck availability and less waste oil disposal."

Saving Fuel

But with the high price of fuel, another potential benefit of synthetics is garnering more interest: fuel economy.

Synthetic lubricants in axles and transmissions have been shown in controlled testing to provide fuel economy savings over mineral-based lubricants of anywhere from 1 to 4 percent. A new generation of these lubes that meet new standards introduced last year by Dana and Eaton show an additional 1 percent or more improvement.

Using a total synthetic lubricant family of products can improve fuel economy savings by as much as 5 percent annually, according to Citgo. The company recently introduced its Citgo HD Greenway program, which features synthetic engine oils, transmission fluid, grease, gear oil, plus an oil analysis program.

However, just switching to a synthetic engine oil will not necessarily improve fuel economy. The key is synthetics offer the ability to create lower-viscosity-grade motor oils than is possible with traditional mineral-oil base stocks: 10W-30s, 5W-40s, even 0W-40s. And those lower viscosities are what give fleets a tool for potentially saving money on fuel.

"You can't get maximum fuel economy by using just a synthetic by itself," says Bob Theisen, manager of technical services for CHS, which sells Cenex brand lubricants. "You need a combination of synthetic and lower viscosity to get the maximum benefit."

Viscosity also has been a factor in gear oils, Theisen says. "It used to be that 85W-140 gear lubricants were the standard viscosity. Now the axle builders and the fleets that use those axles have been made comfortable with the 75W-90 full synthetic."

The problem, Theisen says, is that although lower-viscosity synthetic gear oils have proven themselves, the lower viscosities in engine oils aren't readily accepted by today's fleet operators or engine builders. But that's starting to change.

Viscosity Matters

"I think we're on the brink in North America of seeing a paradigm shift in viscosity selection in diesel engines," says Mark Betner, heavy-duty lubricant manager for Citgo Petroleum. The light-duty diesel builders are leading the way, but heavy-duty will follow, he says.

Why do lower-viscosity oils have the potential to save fuel? The higher the viscosity, the harder the engine has to work to pump it, Betner explains. A 15W-40 oil requires more energy to push it through the engine than a 5W-40. "All that energy has to come from diesel fuel."

In Europe, where lower-viscosity synthetic motor oils are common in heavy-duty trucks, you will see 5W-30, 10W-30, and 10W-40 engine oils as factory fill, says Steve Goodier, director of technology with BP, which markets Castrol lubricants. "For about 10 years we've been marketing a 0W-30 fuel-efficient lubricant [in Europe], Castrol Elixion, and we regularly see numbers of 4 to 6 percent fuel economy improvements from just the engine lubricant." (Elixion is available in a 5W30 in North America.)

On this side of the pond, most synthetic heavy-duty engine oils are 5W-40. Using 5W-40 synthetic motor oils in diesel engines can result in fuel savings of between 1 and 3 percent a year, according to laboratory tests.

"The average consumer doesn't know how to relate to 1 percent, 2 percent," Betner says. "They think that's just not enough. We burn 60 billion gallons of diesel fuel a year in America, and 1 percent savings will save us 600,000 million gallons of fuel a year. Oil companies have not been the most popular business in recent times, so why give the fuel side of the petroleum industry back $180 million a year?"

Betner recalls trying to convince a large fleet maintenance manager in 1982 to switch from straight 30-weight oil to 15W-40. "He looked at me and said 'Son, go back to your engineers and say it will never, ever work in a diesel engine.'" Of course, today, 15W-40 is the industry standard. Betner believes the same thing will happen with lower-viscosity oils.

The gut feeling of many customers is that lower-viscosity oils are too thin to offer proper protection for a hard-working commercial diesel. 

"They're concerned about engine durability," Theisen explains. "Will these lower viscosity oils give them the durability to go to the type of mileage [they're currently getting] on overhauls? Some fleets go to half a million miles before they do an in-frame overhaul - and they definitely do not want any downtime."

You're getting more than adequate film and wear protection with a synthetic motor oil, Betner says. In fact, "we have data showing that a 5W-40 synthetic provides better wear protection than a 15W-40 conventional oil."

Another reason fleets are hesitant to jump into synthetics is that while lab tests may show 1 to 3 percent improvement in fuel economy, seeing the same thing in the field is difficult. 

"I'll never be convinced that the supposed fuel savings with synthetics will make a significant difference vs. the price of fuel," says P.A.M.'s Tapp. There are so many other things that can be done to save fuel, he notes, from aero packages to wide base tires to lightweight components to anti-idling equipment - and, he says, "one sure way to reduce fuel consumption (though not very popular) is to reduce the speed limits."

BP's Goodier also points out that there are many other ways for fleets to save fuel. "Driver training, tire conditions, maintenance of the vehicle, all those factors -- most well-run fleets will be doing this already, and it's in these fleets where fuel efficient lubricants really come into their own."

However, Goodier says, measuring fuel efficiency in the field is extremely difficult. Driving habits, the weather, the season, truck specs, tire inflation, whether you're running in congested cities or mountainous terrain or flat Kansas turnpike, all affect fuel economy - and make it hard to measure a 1 or 2 percent difference due to motor oil. On top of that, Goodier says, it's vital to keep accurate fuel records. "If the driver rounds up to the nearest 10 miles when he fills up, it makes it very, very difficult." 

Betner emphasizes that regardless of how difficult it may be for you to measure the fuel-saving contribution of lower-viscosity synthetic engine oils, there is always a savings. "Regardless of the variables, wider-range heavy-duty engine oils always have the advantage, and that advantage, even in small increments, is huge when you consider many Class 8 vehicles consume over 20,000 gallons of fuel annually."

Then there are the OEMs. One of the reasons lower-viscosity motor oils are widely used in passenger cars and in the European trucking industry is that they are recommended by the vehicle and engine manufacturers.

"The primary current recommendation among diesel engine makers [in North America] is 15W-40," Theisen says. "There are a few manufacturers that recommend a 5W-40 or even a 0W-40 in extreme cold applications, but they recommend you remove those low-viscosity oils when the temperature gets to a certain level. 

"However, there's a lot of activity going on at the engine builder level to look at lower-viscosity oils for these engines. I believe the next common viscosity grade will be a 5W-40."

Figuring the ROI

But, skeptics say, synthetic oils are more expensive - two to three times more than conventional mineral-based oils. Betner says the potential fuel savings alone could pay for that extra cost, not even taking into account savings in engine wear, extended drain intervals and other costs.

"I think fleets would evaluate using a synthetic oil similar to using other higher-performance components in their truck," says Walt Silveira, North America technical manager for Shell Lubricants, which is launching its CJ-4 synthetic Rotella T product in the near future. They are "looking for efficiencies, whether it be fuel economy or improved wear performance, better soot control, better deposit control. Someone who is really looking to use a higher-performance product is going to be very analytical and look at that as a choice they have to make to determine whether they're going to receive the benefits."

Cautioning that it's difficult to make generic statements that will apply to every fleet, ExxonMobil's Kwon says "data we have generated on Mobil Delvac are suggestive of providing longer drain intervals than mineral oil or even semi-synthetics, for lower disposal costs, lower labor costs, leading to a superior value proposition. Our data also suggest fuel economy benefits. So those would go toward the total cost of ownership issue. While the synthetics might be more expensive in terms of initial purchase price, overall you would have a favorable value proposition."

Citgo has developed an electronic calculator to help fleets determine the potential cost savings of using synthetic lubricants, including labor, filter costs, oil usage, oil analysis, vehicle availability/downtime, fuel economy improvements, etc. "In a fleet of 100 vehicles, that's worth about $75,000 a year," Betner says.

In Europe, it has been easier to justify paying more for fuel-efficient, low-viscosity synthetic motor oils.

"In the European market, there has been much more of a focus on the use of synthetic oils," Silveira says. "What we see is a little bit due to the OEM influence - they do promote synthetics in the European market - as well as when you look at the higher cost of fuel in the European market, they have probably been more influenced by looking for fuel economy benefits."

It's important for each fleet to evaluate the potential benefits of synthetic or semi-synthetic lubes vs. cost based on its own unique operations. Those evaluations must be rethought in light of changing fleet operations, changing equipment, changing engine emissions requirements and changing oil specifications.

For instance, P.A.M.'s Tapp says with the advent of the 2007 engines, they tested the CJ-4 version of their supplier's full synthetic motor oil in a couple of test engines starting in late 2005. They took used-oil samples every 5,000 miles to see if they could keep their 150,000-mile drain intervals they had been getting with synthetic oils.

"After analyzing 675,000 miles of sampling data, Mobil's engineers decided that the new oil would not hold up to the oil drain interval of the old Delvac 1 on pre-2007 engines," Tapp says. "At that point our choices were to reduce the oil drain interval to 100,000 with the CJ-4 full synthetic, revert to conventional CJ-4 oil at low oil drain intervals, or move to Mobil's CJ-4 semi-synthetic product with an extended drain interval, but still under 100,000 miles. We did the math and it became a matter of economics to convert the fleet to the semi-synthetic product and still realize some of the benefits of using synthetic oil." 

BP's Goodier believes that eventually, the North American heavy-duty industry will move more and more to semi-synthetic motor oils, and then on to full synthetics with lower viscosity ratings. "The demand for fuel efficiency, the demand for extended drains and reduced operating costs from both the end users and the OEMs will force you down that road."

What Is A Synthetic?

Base oils used to manufacture heavy-duty engine oils are classified into Groups I through V, as defined by the American Petroleum Institute. Synthetic oils fall into groups III, IV and V.

Group IV oils are what you might think of as a "true synthetic" - the process actually results in building a new molecular composition, man-made, synthesized base oil molecules, or Polyalphaolefins (PAOs)This is arguably the very best method, explains Mark Betner, heavy duty lubricant manager for Citgo Petroleum, and is often used for gear oils.

Group III oils are actually derived from crude oil, just as traditional mineral-based oils are. But the Group III base stocks go through an extensive chemical process (hydrocracking, or hydroprocessing), which removes impurities that would ultimately impact the performance of the finished engine oil. This process offers performance very close to that of Group IV oils.

"After you process the crude, you're taking the molecule completely apart chemically and re-assembling them chemically to make the molecule exactly how you want it to look," explains Bob Theisen, manager of technical services for CHS Lubricants.

These Group III base stocks are more likely to be used in engine oils than the totally man-made version, because it is more cost-effective. Betner predicts we may eventually see companies blending Group III and Group IV base stocks to get the best balance of cost and performance.

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Extended Drains: Synthetic Not Magic Bullet

Earlier this year, the Arkansas state Court of Appeals rejected a Little Rock trucking company's claims that Volvo had committed fraud by selling the company trucks with inferior engines. Volvo's defense, which the court agreed with, was that poor maintenance of the engines by Pro Transportation caused the problems.

The court found there was evidence that "Pro was using synthetic motor oil in its trucks and sometimes went 75,000 miles or more between oil changes despite the recommendation of Volvo engineers that synthetic oils be changed every 25,000 miles."

Does that mean you can't use synthetic engine oils to help extend drain intervals? No; what it does mean is that you can't do it without a tightly run maintenance program and oil analysis to support your extended drain program.

"Too often fleets buy into the idea that the oil quality and/or type of oil creates the only basis for an engine oil service interval," says Mark Betner, heavy-duty lubricant manager for Citgo Petroleum. "Citgo is often asked, 'How far can I go on your oil?' In fact, the question should be put back to the fleet as, 'How far can my oil go on your maintenance program and operating conditions?'"

When making a decision to extend, or optimize, your oil drain intervals, there are many factors to take into account, including:

Your engine manufacturer's recommendations

Your oil filter manufacturer's recommendations and filter capability

Operating conditions such as engine idle time, loads/duty cycles, and fuel consumption

Your maintenance operations - Do you perform routine maintenance religiously or miss service periodically? Do you keep good maintenance service records?

An oil analysis program that creates accurate and consistent oil condition information to support the engine oil service interval for each power unit.

Engine oil quality. 

"Synthetic engine oil offers the best opportunity for engine oil service interval optimization," Betner says, "based on the overall synthetic oil's capability of withstanding the harsh environment of heat and oil breakdown over time. However, this never implies the oil can automatically go X miles without implementing the guidelines listed above."

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