Construction equipment owners have long known that a good way to increase productivity and minimize costly unplanned equipment downtime is to participate in a preventive maintenance (PM) program. An integral component of a comprehensive PM program is the analysis of oil and lubricants, through programs like Komatsu America International Co.'s Oil and Wear Analysis (KOWA) program.

"Routine oil analysis helps equipment owners detect and identify abnormalities early and correct them before they become a big problem," said Ray Anderson, Komatsu's Service Development Manager. "The process is simple and inexpensive and it helps prevent unplanned repairs and prolonged, unscheduled downtime, which is certainly the most costly aspect of equipment failure."

KOWA is administered through independent, certified laboratories. "Using independent labs is one assurance of an objective analysis," said Don Day, maintenance manager, J.C. Evans Construction, Austin, Texas. "The labs provide analysis only, and it's up to me to decide which repairs to have done."

Representative oil samples must be taken on a regular basis to ensure accurate analysis, as well as to establish a consistent trend history of a machine's component wear patterns. The scheduling of oil sampling can easily be figured into a PM program.

To ensure that an accurate mix of wear products and lubricant contaminants are present, samples should be taken while the engine runs to circulate the oil or within 30 minutes of machine shutdown. It also is important that samples are not taken from areas where lubricant flow is restricted, or by pouring oil from the filter, as contaminants may settle out of the oil and produce inaccurate results.

"Oil can be drawn from the oil fill openings in the components," Anderson said. "A low-pressure sampling valve is available and can be permanently installed in the engine. This makes it easier and more economical to acquire good, clean samples without having to shut down the machine."

The oil samples are put through both physical testing and spectrochemical analysis. The physical tests performed measure the viscosity, fuel dilution, oxidation and nitration of the oil, as well as the concentrations of water, glycol and fuel soot.

Spectrochemical analysis is used to identify the presence of 21 specific elements that would otherwise go undetected. The results of these tests provide experienced analysts with insight into the source of the machine's wear and can be used to identify a wide range of problems.

J. C. Evans Construction conducts scheduled oil analysis on more than 350 pieces of equipment resulting in 2,000 to 3,000 samples per year, according to its local distributor, Waukesha-Pearce Industries, Inc.

"These tests typically identify one or two problems with our equipment per week," Day said. "We're able to correct problems before any damage is done-problems without oil analysis, would have escalated into full-blown crises."

The problems that the tests have identified range from an air intake leak or an air breather knocked off a transmission, which are simple to rectify before any damage is done, to situations much more involved, and potentially much more expensive, if not caught early.

"We were performing routine maintenance, including oil analysis, on a wheel loader and found a high concentration of wear metal in a sample taken from the differential," Day said. "The oil was changed and resampled with the same results. Our distributor looked at the machine and found bearings that were near failure.

"The oil analysis saved us the cost of having to replace the wheel loader's differential. I hate to think of the losses we would have encountered if we had run the loader until the differential failed." The results from oil analysis also have been shown to significantly decrease maintenance costs when used to identify potential problems for maintenance planning.

KOWA data is integrated into Komatsu's CARE program, a service data-management system. A distributor using the CARE program can link KOWA results to other PM data to further assess wear patterns, identify trends between other types of diagnostic inspections and schedule necessary maintenance when it is most convenient and cost effective for the customer.

The precise, comprehensive reports detailing the results of the oil analysis also are available directly from the independent lab by fax, through the mail, or on an electronic bulletin board system.

Information provided by Komatsu.