Of course, it depends and awful lot on exactly what your trucks are doing, but it’s a good bet that you could be changing oil and filters less frequently if you haven’t attempted to optimize the oil change intervals established for your PM schedules. You purchase engine lubricants just as you do with other consumables for your fleet—fuel, tires, brake linings. You do your best to maximize the use of most consumables, but have you done your best to maximize the life of the engine lubricant you purchase?
Two findings in a recently published report of a study done by the California Integrated Waste Management Board are of particular interest:
• Fleet operators can extend oil change intervals by using higher-quality oil and using oil analysis for determining optimal drain intervals.
• In large engines, high efficiency oil filters are an effective and economical technology for extending oil drain intervals.
Darry Stuart, president and chief executive officer of DWS Fleet Services, would likely agree. He said, “Today’s oil does a phenomenal job. I do not ever remember, during my career, of any engine failure that was caused by a lubricant failure. “I recommend in all cases that fleets use premium filters. If you’re going to try to extend oil drains, the best filter available from the supplier of your choice will give you a bit of a safeguard. Unfortunately, our industry does not have an oil filter restriction gauge available like it does on air filters. It’s likely that filters are only being used through about 30% of their potential service life. Any additional filtration that you can add at a reasonable cost is in my opinion desirable.”
Regarding over-the-road operations, he said, “In reality, we can safely go 40,000 to 50,000 miles between drains assuming you have a quality PM inspection when you do change oil. If I had my way, I would use a deeper oil pan and a bypass filter on every vehicle.”
Extended service interval programs can not only reduce cost in the short term, but also can pay huge dividends in a much larger way. According to Jerry Parker, district sales manager for WIX Filters, by simply doubling an oil change interval, a 50% reduction in oil consumption on both sides of the ledger can be attained—both purchase of new and disposal of used lubricant.
“The reduction on the waste stream of used lubricants represents a cost savings and it also has a significant impact on the environment,” Parker said. “By working with knowledgeable, qualified vendors this transition can be completed with no disruption to daily operations. The rewards generally outweigh the effort.”
Application specific
Optimum drain intervals, even for identical engines, can vary substantially. There can, however, be significant savings offered by extending drain intervals in some applications. This is especially true for over-the-road operators or for fleets that have consistent routes and loads. Such conditions offer the possibility of optimizing and possibly extending drain intervals.
For on-highway applications, most engine manufacturers will recommend a drain interval that depends on the load the vehicle is carrying, the vehicles fuel economy and idle time—basically, the amount of fuel burned. Dan Arcy, OEM technical manager for Shell Lubricants, said, “That makes a lot of sense. Typically, heavier loads or more difficult terrain require more fuel and therefore shorter drain intervals than lighter loads and flat terrain operations. Based on an analysis of the fleet’s operating characteristics, we try to determine if there is an opportunity for extending oil drain intervals, or should the drain interval actually be shortened.”
Arcy went on to say, “We also have to look at what makes sense for the fleet. If they’re going to bring a truck in on a 25,000 mile schedule for greasing, does it make any sense to try to move an oil drain out to 50,000 since the truck is going to be in the shop for half a day or so anyway.”
Stuart would likely agree with such a concern. He said, “A major problem, which can occur when trying to maximize oil drain intervals, is doing multiple PMs in between. You could be adding labor costs that negate any savings you might achieve through an extended oil drain interval.
“We often hear that fleet managers want to look at their trucks more frequently than just during an extended oil change interval. In reality, what ought to be checked during a good pre- and post-trip inspection, which is done every time the truck goes out, should be checked and reported by drivers. The biggest concern, of course, is safety, which is related to brakes and tires. Drivers look at tires every day, and they can tell you the moment brakes start having any problems.”
There is another potential down side of moving to extended drain intervals. Consider a truck that is safely scheduled for a 25,000 mile oil change but missed it for some reason or another. If it goes to 50,000 miles, you might well be compromising the life of the engine.
Oil analysis
The obvious advantage to extended drains is more uptime, an important factor since the truck’s not making any money unless it’s on the road. However there are some responsibilities that go along with an extended drain. John Gaither, PE, director of heavy-duty engineering for Fram Filters, said, “One downside of extended drains is that it requires extra effort on the part of the fleet manager. We recommend using oil analysis regularly. Without the use of oil analysis, we do not recommend extended drains. Once you establish a safe drain interval for a particular engine, I like to see the fleet draw an oil sample halfway through the anticipated drain interval. Then another sample should be drawn at the drain interval.”
On the topic, Donaldson engineers said, “There are few substitutes to the wealth of knowledge gained from regular engine oil analysis. From its chemical and particulate assessments, oil analysis can provide key information on the oil’s viscosity, it’s additive package status, the extent of wear debris, water content, oil acidity, particulate concentrations, and much more.”
Gaither said, “We have a lot of fleets that install oil sampling ports on any equipment coming into service. Then, with the system pressurized the engine running, they can take a sample and the whole process doesn’t take but a minute. If you have to get the oil sample in some other manner, it can become a real nuisance. If you have an oil sampling port installed, we recommend using that port for all samples as opposed to catching oil as it drains from the sump during an oil change. I would very much like to see oil sampled from the exact same port each time.”
Reputable oil analysis vendors are not difficult to find. Most filter manufacturers have an affiliation with at least one of the labs. The easiest thing to do though is to talk to your filter supplier or your oil supplier. In some cases the engine manufacturer can recommend one or do it themselves.
The fleet manager has to recognize that, if the operating conditions change for a vehicle, he may well have to change the drain interval. Shell’s Arcy said, “If they’re running on flat land and the drain interval has been working fine at 40,000 miles, it may have to be shortened substantially if the truck is moved to operations in the mountains. In fact, if any of the parameters that were used to establish the original drain interval change, that drain interval is going to require reevaluation.”
Lube filters
According to the Filter Manufacturers Council, there are filtration products currently available that are designed for extended oil drain intervals. While most filters do an excellent job in filtering, the trend of extending oil drain intervals two to three times the normal service interval has pushed the materials used in the manufacture of filters to the limit. Adhesives, rubber compounds, filter media and even the steel used in spin-on filters needs to be designed to meet the extended period of time they are expected to be in service. Before considering an extended oil drain interval make sure the filter manufacturer will warranty their product when used in such a manner.
Donaldson engineers also reference the Council’s Bulletin TSB-85-1R2 that says, “Under the federal Magnuson-Moss Warranty Act, the Clean Air Act and general principles of the U.S. Federal Trade Commission Act, a manufacturer may not require the use of any brand of filter (or any other article) unless the manufacturer provides the item free of charge under the terms of the warranty.”
Fram Filters’ Gaither said, “With regard to filter choice, you get what you pay for. What you want to find is a filter that is equivalent to or better than the original equipment filter. If you purchase filters from a reputable manufacturer, you know exactly what you can get. Any filter is going to work fine if you run standard change intervals. If, however, you’re going to utilize oil analysis and run extended drain intervals, a standard filter may or may not be what you want. Luber Finer recommends a full synthetic filter be used for extended drain service.”
The media of a full synthetic filter is made of something other than natural fibers, which are usually cellulose. Conventional filter media has a high percentage of natural fibers. Synthetic fibers are typically polyester or fiberglass, which provides high temperature resistance and high strength for long drains. Such fibers increase filter efficiency substantially compared to filters using natural fibers without increasing pressure drop across the filter.
According to Donaldson, one consideration worth noting is the choice of a lube oil filter designed with synthetic, wire-backed filter media. Such designs are far less susceptible to long term heat exposure, and often have superior particulate separation and hold capacity than do most cellulose-based filters. They are often the filter of choice to be coupled with extended drain intervals.
Donaldson Endurance filters are just one such product. These filters are designed for extended oil drain programs for heavy-duty engines and use only synthetic media. According to the manufacturer, they have significantly lower restriction than conventional cellulose media filters.
Extended oil drain intervals are not without risk, and the cost savings they offer should be balanced with engine performance, durability and reliability. With all of the factors affecting the engine oil, it is easy to see why OEM’s have traditionally been conservative in setting recommended oil drain intervals. Stuart’s final advice if you’re going to utilize extended oil drain intervals, “Use good filters, crush them when you change them and dispose of the waste oil properly.”
