Maintenance management: Oil sampling & analysis
| June 12, 2007 |
Would you spend $10 to prevent a major overhaul on a quarter-million dollar machine?
In a capital-intensive business like heavy construction, returns on investments are important and there is no other activity or service procedure in your fleet management that can save you as much money for so little up-front cost than oil sampling.
Whether you are managing a fleet of hundreds or just a backhoe or two there is no piece of equipment too small to benefit from routine oil sampling and analysis and no contractor so small that he can’t save money by doing so.
WHY ANALYZE OIL SAMPLES?
Avoiding mechanical disaster: The most immediate benefit to oil sampling is that it can tell you if a catastrophic engine failure is lurking unseen in one of your pieces of equipment.
But narrowly avoiding engine failures are just part of the picture. In an oil analysis report the wear metals reading shows how your bearings, cylinder liners and other mechanical components are holding up. Wear metals can also alert you to misaligned components, improperly torqued bolts, defective parts and maintenance and service errors. The appearance of contaminants such as fuel, water, glycol or dirt in a sample can pinpoint a clogged filter, leaky seal or bad gasket and give you the opportunity to nip the problem in the bud.
And oil samples not only tell you how your engines are holding up; they also give you information on how well your oil is doing its job. As oil breaks down over time it may not stay in its viscosity grade, the additives degrade and the oil’s ability to suspend soot and neutralize acid is reduced.
Extended drain intervals: Putting issues of engine failure aside, the biggest savings fleet owners can realize from oil sampling is that it gives them the opportunity to extend drain intervals.
Extending oil drain intervals needs to be approached carefully and with guidance from your equipment dealer and lubricant supplier. “It’s a good idea to build a history first, so you have a sense of the condition of the oil and the engine,” says Peter Van Benthuysen, technical support for Shell Lubricants. “I recommend stepping out the drain interval a certain percentage – maybe 25 percent – and then continuing the analysis, paying attention to the wear metals, total viscosity, TBN and the amount of soot that’s in the oil. Then determine what your limits will be on those.” Van Benthuysen cautions there is some risk associated with extended drain intervals. “There are contaminates like fuel, dirt or water in the oil that you might not catch as fast,” he says.
But the biggest savings in extended drain intervals is not so much in the cost of the oil as in the cost of doing the service and the downtime.
A 10,000-hour machine is typically scheduled for 40 oil changes in its lifetime. Multiply 40 times an hour of downtime, times an hour’s worth of what it costs you to field a mechanic and truck, times the cost of disposing the used oil times every machine in your fleet and you’re into some pretty big numbers.
The new emissions-compliant, EGR-based Tier II highway truck engines have made many customers nervous about soot and acid levels. The oil companies developed a new oil standard called CI-4 to help combat these problems. But given the lack of real-world experience on these engines, there’s never been a better reason to sample thoroughly and sample often, says Mark Betner, heavy-duty products manager, Citgo Petroleum.
Resale value: Another important reason to regularly sample and analyze your engine oil is to provide documentation of good maintenance practices when you’re ready to sell that particular piece of equipment.
“A well-trained maintenance technician can use this data to obtain a better understanding on how the equipment is running and if there are any major problems with it,” says Brian Schmidt, off-highway marketing manager, North America, for ChevronTexaco Global Lubricants. “It will also show significant details after major components have been replaced such as main and rod bearings and, in general, how the equipment is now operating. This data can be very valuable and help increase or decrease the asking price for a piece of used equipment.”
WHAT TO LOOK FOR IN AN OIL ANALYSIS SERVICE
Price: The typical retail price for a single oil sample kit runs from $6 to $10 for a basic analysis and $15 to $30 for some of the premium testing services. The kits typically come in packages of ten or more and include a sample jar, instructions, labels and mailing directions.
But oil sampling and analysis services are offered by several different sources – equipment dealers, oil suppliers and private labs – and that has a bearing on price too. Equipment dealers use incentives to promote their services or tie sampling into a maintenance or warranty program. Many industrial or bulk oil suppliers offer free sampling kits and analysis as part of a package of services built into the price of their oil.
Rather than zero in on cost, Jim Burke, off-road marketing manager for Castrol, says his company looks at oil analysis in terms of payback. “Regardless of the number of samples taken our experience has been that for every $1 spent on oil analysis, you get $4 back in savings,” he says. ” This is dependent upon the contractor taking action based on the data.”
Experience: If you choose to shop around for an oil-testing lab or service, Erik Wangsness, director of sales and marketing for Titan Laboratories, recommends you make sure the lab understands and has experience with the equipment you use. “Different manufacturers’ engines and different engines from one OEM will have different components and wear metals at different levels inside the engine,” he says. “You want to be comfortable that the lab you choose has a good background in testing the type of equipment you’re running.”
Lube suppliers will all tell you they know their oil formulations better than their competitors, which is certainly true. What they also offer is a huge database of samples taken from hundreds of different engines and this deep historical knowledge can be useful in analyzing results. “Oil analysis is a trend science.” Betner says. “If a customer has a fleet all running on 60 series Detroit Diesel engines you can give him more accurate interpretation by comparing his results to everything you know about the 60 Series, rather than diesels in general.”
Communication: Another area to explore before deciding on an oil analysis program is how the results are communicated. Most providers send the results in whatever form is most convenient for you. They can mail a copy, fax the results, send you an e-mail or post the results on a website and tell you via e-mail when they’re ready.
Regardless of the method used, the sources queried for this article say they will get on the phone and call contractors immediately if the test results reveal any red flags or critical situations.
Results through the mail can take up to seven to 10 days. This can be a long time for some operations, but sufficient for equipment managers who are interested only in guarding against unseen catastrophic failures and know they’ll get a phone call on those. Fax, e-mail and Internet results can be delivered in as little as a few hours to a day after receiving the sample.
Internet connections: Internet-based results posted on a secure server the equipment manager accesses from his computer is most advantageous to equipment managers who oversee larger fleets and do a lot of equipment service and cost analysis.
“The majority of customers want to get the results, know that they’re OK and then move on,” says Joe Nixon, coordinator of services for ConocoPhillips. “But there is a minority of customers who want to collect all that data, analyze it, compare trends and study it.” For these customers, Internet sites have that capability and the ability to have multiple people in different locations looking at the same reports at the same time.
“The Internet gives you some flexibility to sort information by criticals or status. You can pull a unit number and store the information without printing it and putting it in files,” Wangsness says. Still, only about 10 percent of contractors use Internet-based oil sample reporting, primarily because technicians and equipment managers don’t spend much time sitting in front of a computer, he says.
Training: While oil testing is a sophisticated science, interpreting the results does not require a Ph.D. thanks to the fact most providers offer some training and post the results with clear, plain-English interpretations.
“A couple of hours of training will let you know what the wear metals are, what the physical properties are, what the viscosity means,” Nixon says. “By taking a simple eight-hour lube course, you won’t be an expert, but at least you’ll know what you’re looking at. Most lube companies provide this.”
For in-person training you can contact your equipment dealer, lube supplier, or local testing labs. These services can even be built into the specs on bids for your business. Wangsness also notes that the testing labs you use can be a valuable source of information for almost any question you may have. “We assist customers over the telephone every day with all aspects of oil analysis programs – setting up programs, what and how to sample, understanding reports, etc.,” he says.
GETTING DOWN TO DETAILS
When to sample: “Most people will sample at the drain,” says Van Benthuysen. “But it’s often more beneficial to sample a week or so before you drain the oil. That way you will have the results back by the time you’re ready to drain the oil. If you have the vehicle in the shop and the oil analysis says there is something that needs attention, you can do it while the machine is still in the shop.”
How samples are taken: The crudest way to take a sample is to remove the oil-pan drain plug and stick the sample jar under the resulting flow. This method has the disadvantage of being messy and is prone to contamination. A better method is to use one of the kits that provide a length of clear plastic tubing and a suction device to extract the sample from either the oil fill hole or dipstick hole.
The most convenient method is to install an oil sampling port on the engine or the oil line. There are a lot of different systems that do this and they all give you the ability to take an oil sample when the engine is running.
What to test for: A basic, no frills sample should test for oil viscosity, SAE grade, soot, silicon (dirt), fuel dilution, water and antifreeze. It should also screen for visible solids or metals and give you a parts-per-million count on wear metals and additives. An upgrade from that basic package would include a reading on total base number (TBN) and total acid number (TAN), a particle count and tests for oxidation, nitration and sulfation.
Testing used equipment for sale: If you are considering buying a piece of used equipment and the seller doesn’t have a documented history of oil analysis, an oil sample couldn’t hurt as long as you know the limitations of a single sample. If the oil in the crankcase is brand new, the lab will tell you so and you’ll have just burned $10 – fresh oil tells no tales. But if the oil has about 100 hours on it you can check for silicon, soot, water, antifreeze or fuel dilution and get some idea of how tight the engine is. Wear metals can be difficult to interpret without a history or trend, but your lab can advise you if any of these are too far outside the margins.
From our partners
Snow Valley Ski Club in Edmonton, Alberta, Canada, operates seven days a…