There are a lot of numbers and reports to watch when setting up an extended oil drain program. In doing so, a fleet manager can run the risk of ignoring what his technicians in the field are experiencing, says Richard LeFrancois, a heavy equipment fleet management consultant.
LeFrancois says he doesn’t discount the value of computers and being able to diagnose machines with telematics and laptops, but the art of listening to a machine is a skill that’s fading away as the older technicians retire. “I went through that period of transition, from the older guys to younger guys who didn’t have that experience. Fleet managers used to seek out the input of the older guys on a daily basis and incorporate them into the process. But, in the past few years, we’ve lost a lot of that institutional knowledge that had been gained over the past 30 or 40 years. The field technicians, fuelers and oilers are ground zero for the machines because they’re touching the machine almost every night.”
SOLUTION:
When you embark on an extended oil drain program, make sure you get buy-in from everybody – from the higher ups to the guys in the field. Make sure the guys in the field know what you’re doing and that you want their input. Use your computers, as well as sight, sound, smell and touch.
2.
GO CHEAP ON THE OIL
“Everybody I’ve talked to says you need to use a quality oil,” LeFrancois says. “You can’t start with cheap oil.”
While the goal of extending oil drains is to save money, the oil must still be robust enough to go the distance and protect your engines. Inexpensive oils generally have less robust base oil and additive packages, and these are what protect the engine from wear.
That being said, the most expensive oil may not be the right solution either, says Jami Melani, field engineering/technical services manager for Castrol. “The key is that whatever oil you buy, you want to get the most useful life out of it,” Melani says. “Full synthetic oil is expensive, and our experience is that a semi-synthetic provides excellent protection and extended drain capability.”
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Financially, it is counterproductive to use the most expensive oil if a lower cost product will do the job. Many of the full synthetic oils are designed for over-the-road trucking, where their low viscosity formulas can improve fuel economy by 1 or 2 percent. However, in off-road equipment fleets, the viscosity/fuel efficiency advantages have not become a concern yet. Some heavy equipment contractors, however, will use full synthetics in extremely cold climates where higher viscosities may make equipment hard to start.
SOLUTON:
Consult with your lube oil supplier for recommendations, and ask him if other contractors have had good results with extended drains on semi-synthetics or other less expensive formulas. You may also want to run a test trial on just one machine to see how far you can push a medium priced oil before wear metals show up or the oil starts to degrade.
3.
IGNORE NEW ENGINE TECHNOLOGY
Don’t assume that because you have two machines of the same brand, size and engine that they will perform the same in an extended oil drain environment. If the age of these two machines varies – sometimes as little as just a few months – they may have different injectors, different horsepower and torque bands, and radically different emissions controls. These can alter the results you get back from your oil samples.
“At one point, when I was working with Cat 3406 engines, we could cover most of the applications with about three different injectors,” says Melani. “Today, you have to have a specific injector for almost each horsepower class for that engine.”
Some manufacturers also use different alloys and materials in their engine blocks, says Melani. “Components in the engine block will leach out into the oil and give you a bunch of false positives. You may think its coming from error or something else, but it’s actually leaching out of the block.” This does not hurt the engine or the oil, but it does create what Melani calls “noise,” or false positives in the oil samples early in the engine’s life.
Soot can be a factor, and is often the first element to condemn an oil, says LeFrancois. “Soot is worse than it used to be, and you can’t trap soot in a filter because it’s a half-micron in size,” he says. Once soot reaches the saturation point, the oil becomes thicker and harder to pump through the engine. Soot levels increased dramatically in Tier 3 and Tier 4 Interim engines when manufacturers increased exhaust gas recirculation (EGR) rates. The newest engines using selective catalytic reduction (SCR) technology have lower rates of soot formation, but soot levels still vary widely depending on the manufacturer and idle rates.
Tier 4 Final engines also tend to run hotter than their predecessors, and that may shorten the life of your oil as well, says Corey Taylor, senior development technologist for Castrol’s global lubricants technology team. Different OEMs’ engines will run at different temperatures. As a result, some fleet managers are dialing back the hours between oil changes, he says.
Heat increases oxidation in the oil, causing it to get thicker. “When you are extending drains, you don’t want to come anywhere near that point,” Taylor says. Things will go bad quickly and get out of control. You want to stop the process before it gets to that point.
SOLUTION:
Consult with your equipment OEM before launching any extended drain programs, and don’t combine oil sample results of old engines with new engines. Also, note that a new diesel oil lube standard (right now its being called PC-11, or “proposed category” 11) is being developed and tested by all the OEMs and major oil companies, Taylor says. One of the major goals of the PC-11 oils will be to provide better oxidative stability to counteract the excessive heat generated by emission compliant engines. Expect the new oils to become available in late 2016 or early 2017.
4.
RELY ON OLD TAN/TBN RATIOS
Another metric that fleet managers used in the past to judge oil life, the TAN/TBN ratio, has changed in the age of the Tier 4 Final engine. TAN is the total acid number and TBN is the total base number. As the oil ages, the TAN goes up, making the engine oil more acidic. The TBN is the measure of the alkaline additives oil companies put in their lube oils to counteract this acidity.
As the TAN increases, the TBN decreases. If you plot their concentrations from an oil sampling report on a graph, the point where the two lines intersect is where many fleet managers historically decided it was time to change the oil, says Melani. But, that changed when fuel refiners switched to ultra low sulfur diesel in 2010-11 in order to meet the requirements of new emission control regulations. Since sulfur in the fuel creates acids during combustion, the low sulfur fuels tended to acidify much slower.
“TBN and TAN tend to cross at a low angle today,” Melani says. “There isn’t a rapid gain or loss of either one, and the useful life of the oil can go much further.”
SOLUTION:
Don’t rely on old rules of thumb about TAN/TBN, and consult with your OEM and oil supplier about when they think you should change the oil.
5.
GRAB A SAMPLE FROM THE SUMP
Taking an accurate oil sample requires a certain level of scientific precision that not all service techs understand. Melani describes four different ways techs sample oil, going from the the worst, to the best:
• Dipping. The worst sample method is to dip your sample vessel in the oil that has already drained out of the engine.
• Swiping a sample from the oil stream. This is where the tech unscrews the oil drain plug, waits 10 seconds, and then runs the sample bottle under the stream of oil. The oil at the bottom of the sump or drain pan has collected a high percentage of wear metals and heavy particles. It’s the dirtiest possible place to sample oil and will give you skewed results.
• Vampire pump. This method is acceptable providing the engine is up to temperature and the sample tube is the correct length.
• Sample ports. Aftermarket sample ports are quick and convenient devices, and usually the most accurate way to draw a sample. But they can render skewed results if they’re put in the wrong place. A lot of techs put them on a long, straight oil journal running on the side of the engine because it’s easy to access. But, the oil flowing past these spots tends to be cleaner than average, and thus, renders inaccurate results. For the most accurate results, your sample port should tap into the block somewhere just downstream of a right angle turn in the flow of oil through the engine. This will mix up the particles in the oil enough to give you the most accurate sample possible.
SOLUTION:
Many OEMs are now putting sample ports on their engines and these will be in the most advantageous place. If you’re retrofitting a port onto an existing engine, make sure it’s in a spot where the oil flow is somewhat turbulent, or consult the engine OEM for advice.
