EXTENDING OIL DRAINS: Back to the basics
With newer engines putting more demands on engine oil, extended oil drain intervals need to be handled carefully.
Deborah Lockridge
Senior Editor
When new engines were introduced to meet emissions standards that went into effect in October of 2002, there was widespread concern that extended oil drain intervals might be severely curtailed with the new engines. But most fleets have discovered they can still extend oil drain intervals, some just as far as before.
"We all expected that there were going to be dramatic reductions in oil drain intervals, but we haven't seen that," says Jim Weaver, executive vice president of T.F. Hudgins, makers of bypass filter Spinner II. "There have been slight reductions, depending on the industry, but it's not like it went from 50,000 miles to 10,000 miles."
Kevin Kroger, president of filter maker Puradyn, reports similar results. "We have some that are telling us they haven't seen much difference at all. Some fleets we've spoken with are not able to go out as far as they used to."
Oil manufacturers report similar stories. Alex Bolkhovsky, commercial vehicle lubricant technical adviser at ExxonMobil, notes that most fleets he knows dropped their oil drain intervals on the new engines back to engine manufacturer recommendations until they were able to see how they performed.
"We've had a couple years on the new engines now, and the good news is our customers using our premium products have been able to maintain the drain intervals they did before the new engines," Bolkhovsky says. "We've seen very few cases of anyone having to stick with the reduced levels."
That's not to say that the new engines don't create some issues you need to be aware of, including increased levels of soot and acid being put into the oil. While the new engine oils that were developed to work in the low-emissions engines appear to be meeting the challenge for the most part, extended oil drain programs need to be handled more carefully than ever before.
Done correctly, an extended oil-drain program can save money on maintenance costs - less oil, fewer filters, less labor involved in changing the oil, less used oil/filter disposal costs, more uptime for trucks to earn revenue. But if it's not done right, excessive wear on the engine caused by oil that's no longer doing its job can end up costing you more down the road.
"I think the biggest drawback to extended oil drains is making sure you don't extend it so much that you start causing engine wear, because then you're going in the wrong direction," says Miguel Sanchez, brand manager, BP Lubricants Americas (Castrol). "You're going to spend more money on overhauls or other big repairs, not only for the cost of the repairs but also for the large amount of downtime."
One of the first things to ask yourself is, what are you trying to accomplish by extending your oil drain intervals? Is it reduced maintenance costs, reduced downtime, using less oil? How far are you trying to extend it?
Some fleets are simply not good candidates for extending oil drains. A lot of stop-and-go driving and a lot of idling time, as is seen in trash truck fleets, is especially hard on the oil, so you may not be able to extend your drain intervals without risking damage to your engines. Other factors that may adversely affect the ability to extend drains include low fuel economy, as well as dirty and dusty conditions that are more likely to get contaminants into the oil.
Extended oil drains also need to fit in with a fleet's other maintenance practices, says Dan Arcy, technical marketing manager with Shell Lubricants. "Let's say they're running 18,000-mile oil drains and they want to take it out to 24,000 miles. Does it make sense to do that if they have to bring it in at 18,000 miles anyway to do a grease job? The cost of having it down and the extra scheduling and downtime may not make it cost-effective. I've seen a number of cases where the timetables just did not match up."
The makeup of your fleet also has a lot to do with whether you can handle an extended drain program. Do you have a mix of pre-2002 and newer engines? If so, can you handle a program of two different oil drain intervals, perhaps a longer one for the older engines and a shorter one for the newer ones? What if you have some trucks that are running short-haul LTL, some that are hauling construction equipment, and some pulling van trailers in linehaul? These will all need different oil drain intervals, unless you want to pull them all back to the lowest common denominator.
"We do have some fleets out there with separate drain intervals for each of those," Arcy says. "Some fleets have the capability to manage those type of things. Others don't."
Another vital factor in a successful extended oil drain program is a tightly controlled preventive maintenance program, one where you can be sure oil drains are done on schedule. Improperly managed oil-drain intervals can lead to accelerated engine wear and costly engine rebuilds, erasing any savings you realized by extending the drains in the first place.
"There's inherent risk with extended service intervals," says Gary Parsons, manager of commercial automotive at ChevronTexaco. "Say you're changing the oil every 20,000 miles, and you know the oil has the capability of going out to 40,000 or 45,000 miles. If you happen to miss an oil change, you're still OK. If you're doing extended drains, and you miss that oil change, then you're running that oil right out to the end of its useful life. So it comes down to having a rigorous preventive maintenance program and being able to monitor and track and schedule the maintenance when it's required."
Once you've looked at these factors and have a goal in mind for extended oil drains, it's time to talk to your engine manufacturer, oil supplier and filter maker.
"The OEM warranty and guarantees are based on following their recommended drain intervals," Parsons says. "Fleets should work with the OEM and the lubricant supplier to safely extend drain intervals, if they can."
It's important to communicate with all parties involved. "Be aware that engine oil, engine and filter manufacturers may have varying opinions on engine oil drain interval capability, resulting in concerns for engine life and ultimately engine warranty coverage," says Mark Betner, heavy duty lubricants manager for CITGO. "It may be a good practice to set up a meeting to discuss your engine oil drain interval goals." Bring oil analysis results to back up your goals. If the oil analysis provider is separate from your oil company, get them involved, as well.
OIL ANALYSIS
Oil analysis is an absolute must if you want to extend your drain intervals. It should be checked at every oil change at the minimum. Most engine oil providers offer oil analysis in one form or another, and there are independent labs, as well. Who you choose may hinge on how well they can assist you in implementing your oil analysis program and interpreting the results.
If you have not done oil analysis in the past, you need to develop a baseline before you start experimenting with longer drain intervals. Establishing a trend and history should be done with several oil samples taken consistently and accurately for each power unit over several engine oil drain intervals.
If these baseline tests show abnormal or critical levels of contaminants such as dirt, coolant, fuel or soot, you need to do some work on your preventive maintenance practices before you can even think about extending oil drains.
"Otherwise, you're living in the danger zone," says CITGO's Betner. "These contaminants are a result of inadequate air induction, cooling system and fueling system maintenance, which can be corrected. No oil, no matter how good, can overcome these contaminants when abnormal or critical levels of contaminant are reported."
Make sure your oil analysis includes TBN, or BN, or a newer test called TAN. This indicates the ability of the oil to neutralize acids. Some standard oil analysis packages do not include this, but it's especially important with the newer engines.
"Once the BN reaches approximately half of the new oil value, it declines fairly rapidly," says Barry Williams, president and CEO of Predictive Maintenance Services. "Say there are 100 units of BN additive and it takes 10 units to neutralize a unit of acid. That's 10% of the new oil. When the additive is half gone - 50 units of BN additive left - the same 10 units equates to 20% of the remaining additive."
Williams also recommends testing oxidation and nitration levels. These two tests indicate sludge, varnish and other deposits are forming as additives are depleting. These deposits can cause corrosive wear and clog filters.
Soot levels and wear metals are also important areas to keep an eye on, especially with the new engines. Keep an eye on the viscosity of the oil. If it's thickening quickly, the soot level may be too high, and can lead to increased wear rates.
ExxonMobil's Bolkhovsky recommends taking a step-by-step approach to extending oil drain intervals.
"Let's say you're going out to 40,000 miles as your targeted goal for oil drain extension and you're currently at 20,000 miles," he says. "You probably don't want to move from 20,000 to 40,000 in one step, taking a big risk with your equipment. You move to 30,000 miles and look at what the data is telling you, then your next step would probably be to 40,000."
If your fleet is large enough, Bolkhovsky suggests taking a small subset of your equipment and testing the extended drains on them first. Test the vehicles that are run under the most severe conditions first. If they can handle the extended drain interval, then your less-stressed engines should have no problem.
You also want to check at oil drain intervals beyond where you want to end up to make sure you have a safety factor built in.
"If you want to go to 30,000, you might want to take it out to 35,000 or 38,000 and then back it off a little to make sure there's a safety factor there," says Spinner II's Weaver.
The Filter Manufacturers Council recommends an even more conservative approach: Do oil analysis at the normal service interval, then in increments of 20% thereafter (i.e., 16,000 miles, 19,200 miles, 22,400 miles, 25,600 miles, 28,800 miles) until the analysis shows the useful life of the oil deteriorating. Once the maximum limit on the oil is reached, the change interval should be set at the mileage of the previous sampling prior to indications of oil deterioration.
As you look at oil analysis results, Bolkhovsky emphasizes, keep in mind that you're looking for trends. Make sure none of the potential problem areas suddenly start taking off.
"Wear is one of the big ones," he says. When anti-wear additives start wearing out, or soot builds up to the point where the oil is no longer protecting against wear like it should, wear metals in the oil will start to rise. "What you will see is, at some point the level of wear metals just takes off in this exponential curve." You'll want to back your drain intervals off so you change your oil before it gets to that point.
CITGO's Mark Betner notes that an increasing level of contaminants, such as wear metals, is normal due to the amount of time the oil's been in the engine.
"Say you doubled your drain interval," Betner explains. "As long as the increase in wear metals is proportional - say it's 10 at drain interval A and 20 at drain interval B - that's OK, because it means the rate of wear is constant. But if it jumped to 100 when you went to B, that's an indication the oil is not providing the same level of wear protection."
FILTRATION
"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," says the Filter Manufacturers Council in a technical bulletin on extended oil drain intervals. "Adhesives, rubber compounds, filter media, and even the steel construction in spin-on filters needs to be designed to meet the extended periods 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 this manner."
You may even need a different filter. For instance, Baldwin makes a severe service filter that offers extra efficiency and capacity to handle extended drain intervals. Check with your engine manufacturer and filter maker for the appropriate filter.
You also might want to consider adding bypass filtration, for two reasons.
One, they add capacity. The more oil there is in your system, the more it can dilute the soot, acid and other harmful contaminants. Adding more lubricant to the system also helps dissipate some of the additional heat generated when cooling the exhaust gases on EGR engines.
Two, they help keep the oil cleaner.
"Because it's a slow flow area, you can use all types of media to do a whole lot better job of cleaning the oil of contamination, moisture and sludge," says Chris Greeson, senior technical service manager at Wix Filters.
There are two types of bypass filters. There are ones that work much like a traditional filter, putting oil through filter media to trap contaminants. This can include surface layer filtration, which is your standard pleated media made of various materials, or depth filtration, which uses a very thick media to take out contaminants. The second type are centrifugal filters, which "spin out" contaminants and claim to remove soot better than other types of filtration. Some centrifugal filters also have special chambers that are designed to evaporate water out of the oil. At least one, Puradyn, claims to replenish worn-out additives as well.
Some aftermarket filter advertising claims might make you think that all you need to extend your oil drain intervals is to buy their filter. ChevronTexaco's Gary Parsons advises fleets against relying heavily on just the filter.
"They shouldn't assume just by putting a higher quality filter on will allow them to extend their service intervals," he says. "When it comes to the life of the oil, the filtration isn't usually the condemning limit. It's more the ability of the oil to neutralize acid." As for filters removing soot, he notes that if the oil is doing its job and keeping the soot dispersed, the particles will be too small - typically .2 microns - to be caught by most filters.
Oil makers are also wary of filters that put additives back into the oil.
"I think every major oil company would agree, that once that oil is in the can, don't mess with it," CITGO's Betner says. "We spent $15 million on CI-4 alone creating a formula that would be licensed and approved by the American Petroleum Institute. If it were so easy to change that formula by putting something in after the fact by way of a filter, then we spent a lot of money on nothing. These oils are balanced to get them as far as you can possibly go."
Puradyn's Kroger defends their product. "You can't just dump additives back into the oil; that's not going to work. That's why we've done some painstaking work on maintaining the formulation of our additive package and the method by which the additives are added back into the oil. We are talking to several different oil companies, so it's not like we're doing this blindly."
CHOICE OF OIL
API CI-4 Plus is the newest oil designation, designed to work with the new engines. The "Plus," added this year, tweaked the original API CI-4 requirements in light of some issues that had arisen since the new engines have been in service. CI-4 Plus oils are intended to provide greater viscosity control in respect to both soot loading and viscosity breakdown, or what is technically referred to as shear stability.
Oil manufacturers recommend that beyond the API classification, you should look to "premium" oils in order to extend drain intervals. "The premium oils definitely have the capability of going extended drains," says Shell's Arcy. "For instance, we test Shell Rotella T to way beyond your standard drain intervals. If you're wanting to go out to 50,000 miles, buy from a company that has actually tested out to 50,000 miles."
There is some evidence that synthetic oils can help extend oil drain intervals, but you have to carefully balance the price premium against expected savings. You may need to look beyond extending your drains and consider other benefits of synthetics, such as superior cold-weather starting and improved fuel mileage.
"Synthetic base oil tends to be able to survive the impact of heat longer, therefore the additive system is not under as great a stress, and the overall package is more durable in some of the areas that tend to break oil down," Betner says.
However, he warns fleet managers that synthetics are not a magic bullet when it comes to oil drain intervals.
"Synthetic oil can be misunderstood or misused in light of the many factors affecting drain interval," he says. "Keep in mind that various types of contaminants can be the limiting factor, and synthetic oils cannot overcome the negative impact of some of these contaminants, such as dirt and coolant contamination."
Even if you've adhered to all these recommendations to the letter, it's important to keep in mind that savings from extended oil drains are a long-term thing.
"You have to understand that these will not be next-day savings," says Castrol's Sanchez. "The way to look at this is take a period of time, a quarter or six months or a year, and see how your trucks are performing, then do your numbers and understand where and how you're saving that money."
