Most of the latest premium oils meet the CJ-4 standard for 2007 engines, which requires reduced consumption – one quality of a superior oil. Less oil burned also means, on 2007 engines, less frequent cleaning of the diesel particulate filter.
Even with its higher cost, premium oil has the potential to save money with fewer engine repairs, longer engine life and extended oil changes that save far more than simply the cost of the oil. But other savings can accrue as well. If the premium oil has a lower viscosity in frigid temperatures, it can protect the engine better at cold start, reduce idling, and save on battery and starter repairs. Some fully synthetic oils also improve fuel economy.
engine repairs, longer engine life and extended oil changes that save far more than simply the cost of the oil. But other savings can accrue as well. If the premium oil has a lower viscosity in frigid temperatures, it can protect the engine better at cold start, reduce idling, and save on battery and starter repairs. Some fully synthetic oils also improve fuel economy.
“Oil companies offer two or three performance levels,” says Mark Betner, Citgo Petroleum’s heavy-duty product manager. “Better oils last longer, neutralize more acid, and handle more soot. Why not take advantage of that?”
Many owner-operators change oil conservatively – at about 15,000 miles. But this is not your father’s oil, especially if you’re using the higher grade oils. Depending on how you operate, a change interval once considered appropriate might not be right today. Being willing to extend your change interval may be required to make the most expensive oils pay for their premium.
WHAT’S SO DIFFERENT?
Engine oil isn’t a commodity. There are significant differences among products. A refiner willing to put extra dollars into ultra-sophisticated refining or exotic additives can produce an oil that will resist breakdown longer, pump better at cold temperatures, and perhaps maintain acid protection with less ash. This last benefit allows use of superior CJ-4 oil – the new category for 2007 engines – even with higher-sulfur fuels.
Oils in the past were merely distilled out of crude petroleum, using heat and pressure to isolate those fractions of the barrel that had the right lubricity and viscosity, compared to the thicker and thinner stuff. These oils isolated by heat and pressure are called Group 1 base stocks. But as time went by, pioneers such as Conoco-Phillips developed a more sophisticated refining technique, which Reginald Dias, director of commercial products at ConocoPhillips, says is termed “hydro-cracking.” This allows impurities to be removed through chemical reactions, not just through heat and pressure, resulting in Group 2 base stocks.
“All modern heavy-duty engine mineral oils are based on this technology,” says Steve Goodier, technology director at BP North America, which makes Castrol oils. The result is oil that holds up better under the high heat and oxygen present in the crankcase, a quality called “oxygen stability.” Since this means a reduction in the portion of the oil that is susceptible to oxidation, it actually reduces the acids in the crankcase. This is exactly what ExxonMobil was able to do with its better CJ-4 oils in order to guarantee acid protection that is equal to that of its CI-4 oils while also meeting the CJ-4 requirement for lower ash, says ExxonMobil’s Doug Pond, a products adviser. “We have one of the highest TBN levels at 10.5, but we want to stress TBN retention.” Pond reports that Mobil Delvac 1300 Super’s CJ-4 actually retains TBN longer than the company’s CI-4 because of its more highly refined base stock.
Fully synthetic oils are derived through a chemical process, taking components of the crude oil apart chemically and reassembling them in a completely different form. “Synthetics have better oxidation and thermal stability, film strength and better low-temperature properties,” Dias says.
As for viscosity, customers often place too much importance on it and misunderstand its function. “What’s important is dynamic viscosity,” argues Goodier, who points to his company’s fully synthetic Castrol Elixion 5W-30. “Traditional viscosity determines how long oil takes to pour through an orifice. Elixion passes the High Temperature High Shear test that simulates viscosity in a journal bearing.”
This lower viscosity can have big cost advantages, including fuel economy and parts protection on cold mornings.
WHERE DO YOU SAVE?
Even if you change your oil at a standard, conservative interval, you are likely to save by using premium oils. Better oil combats wear more effectively, and that means fewer repairs as an engine ages and a longer life till overhaul. An engine that effectively runs 1 million miles instead of 800,000 reduces the cost per mile of that overhaul 20 percent.
Many of today’s top oils differ from their less expensive brothers because they pass the CJ-4 standard. It’s not the sole difference, but it’s a distinction that assures superior quality.
Shell Rotella T with Triple Protection, the company’s premium oil, is “targeted toward the owner-operator and small fleet because they keep their trucks longer, and therefore want the extra protection,” says Dan Arcy, technical marketing manager. He points out that extra protection could come in handy “if you decide to hold onto your trucks a little longer waiting to see what happens with the 2007 vehicles.”
Shell’s Rimula Super also meets or exceeds CJ-4 specs, Arcy says. “But it doesn’t exceed the specs to the extent that Rotella does. Why not get something that exceeds the specifications?” Rotella T with Triple Protection scored 1,400 out of 1,400 possible points on the Cummins ISM injector screw test. The parts looked smooth, rather than slightly scored after the demanding test, conducted under adverse soot and heat conditions. The injector screw is one of the toughest parts in the engine to lubricate because it runs dry under certain conditions. Such protection could keep you from having to replace injection train parts as your engine passes the 500,000- or 600,000-mile mark.
Other Shell tests show wear of parts while running Rotella T CJ-4 is as little as half the wear from running Shell’s CI-4.
ConocoPhillips’ Guardol ECT and Kendall Super DXA, both synthetic blends combining Group 2 base stocks with synthetics, have additives that reduce lead corrosion in the bearings, Dias says. Also, “With excellent soot dispersion, it protects the engine from abrasive wear and helps to keep viscosity under control.” Soot dispersion keeps the soot from making the oil gritty and grinding parts like sandpaper. Keeping the soot dispersed also keeps the oil from thickening. Thicker oil won’t properly flow to the parts, creating conditions similar to a cold-engine start.
Deposit control has greatly improved in all CJ-4 oils. That’s critical to long engine life because if an engine survives to old age without parts damage – and most that are well maintained do – overhauls are determined simply by oil consumption, which normally depends more on deposits than actual wear of piston rings and liners.
Chevron’s Delo 400 Multigrade LE and Texaco Premium TDX EC provide premium performance in engine durability, wear control and other areas, says Mike Dargento, global commercial sector manager.
Oils that have expensive low-ash or non-ash TBN additives allow you to run CJ-4 even with an older engine using low-sulfur diesel, versus ultra-low-sulfur diesel. The same is true when an oil’s greater oxidation stability preserves TBN levels under those same conditions. All CJ-4s are backward compatible and allow you to run even 100 percent LSD with – at worst – a slight reduction in your change interval.
Aside from normal wear, there’s the critical issue of cold starts. “Some engine makers recommend 15W-40 only down to 15 degrees Fahrenheit,” says Citgo’s Betner. “A 5W-40 will give you a 35- to 40-degree lower temperature capability while giving you the same high temperature protection as a 15W-40.”
With ConocoPhillips’ Guardol ECT and Kendall XA, both synthetic blends, the “better low-temperature properties help when you need to start frequently in frigid conditions,” Dias says. “Their characteristics help to get oil to the parts more quickly. This reduces wear and enhances engine protection.”
Savings from better cold-flow characteristics will include not only longer engine life to overhaul and fewer repairs, but less need for idling and less stress on batteries and starters.
Synthetics even have the general characteristic of reducing not just wear, but also the amount of power required to turn the engine. An oil with a 5W-40 rating, such as Citgo’s Citguard Syndurance, or a 5W-30 rating, such as Castrol Elixion, has a lower viscosity at high temperatures, which means less internal engine drag and better fuel economy.
Some fleets have experienced fuel savings as high as 4 percent, BP’s Goodier says. In a truck running 120,000 miles per year and getting 6 mpg, that means saving 800 gallons. At $3 a gallon, that would be $2,400 in annual savings.
Premium oil’s real payoff is extended change intervals. For those skittish about extended intervals, experts suggest relying on oil analysis as a backup. “Work with an oil provider with a legitimate analysis program and establish a trend,” Betner says. “Stay in a narrow range and don’t push the envelope.”
In other words, slowly increase intervals.
The potential savings from extended drains vary based on “operating profile and the maintenance programs and lubricating products currently in use,” Dargento says.
Chevron’s business managers can help figure savings based on factors such as your labor costs, downtime and miles run per year.
Betner suggests using the manufacturer’s recommendations as a starting point before evaluating your maintenance practices. Are you keeping your cooling system corrosion inhibitors in good condition, which protects both the oil and engine? Are you certain your air cleaner and intake system are keeping dust out of the engine? Are you using good fuel that won’t cause injector seal deterioration, leaks and fuel dilution?
A truck hauling overweight loads and getting 3 miles per gallon is not a good candidate. You have to be getting good fuel economy with minimal idling.
“Where the savings come from is in downtime and labor,” Arcy says. “A common scenario would be extending drains 10 percent, which will save you one oil change per year.”
The best fully synthetic oils may allow a doubling of change intervals, Goodier says.
ExxonMobil’s Pond says that, under the right conditions, using Mobil Delvac 1 fully synthetic can extend change intervals three to four times, which “means you have paid back the first cost of the oil many times over.”
SAVE SOME ON THE FRONT END
"There probably should be some minimum standards. But as long as the ...