Detective work and truck-fleet management might look to be very different activities at first glance, but let’s get a magnifying glass out and investigate this mystery a bit further. In fact, we’ll use a full-blown microscope, plus other sophisticated laboratory equipment. That’s how it works at a professional oil-analysis lab, where technicians work to uncover one or more mechanical or chemical villains who are plotting the premeditated murder of a diesel engine in the near future.

“We’re investigators, all right,” says Rod Raymond of the WearCheck Canada lab in Mississauga, Ont., one of fewer than a dozen commercial labs conducting oil-analysis work in Canada. “We focus on spotting the early warning signs of engine wear or lubricating-fluid contamination that can cause anything from a sudden mechanical breakdown out on the highway to a significantly shortened service life for an engine, transmission, differential, or similar component.”

It’s the type of in-depth check a lot of truck operators would do well to consider in this era of ever-extended oil-drain intervals. In some cases, engine manufacturers mandate it as part of their warranty programs. In general, it just seems to make good sense, especially when you start pushing out your drain intervals.

Yet some maintenance managers question the merits of the procedure. Engines are built for extended service and warranties are comprehensive, after all. Plus, more fleets are turning over their equipment on shorter cycles. These things leave fleet managers to wonder whether the process is cost-effective-especially when their test results fail to turn up indications of potentially critical problems.

At reputable labs, there’s no doubt that the samples are put through their paces. At WearCheck Canada, for example, a crankcase-oil sample from a tractor’s diesel engine is assessed in three categories: contamination, wear, and oil condition.

“Contamination” is indicated by the presence of silicon, potassium, sodium, fuel, glycol, water, or soot in the sample; “wear” by evidence of sulfation or nitration, plus the levels of iron, nickel, chromium, titanium, copper, aluminum, tin, lead, or silver; and “oil condition” is assessed by determining the viscosity (ability of the oil to flow freely) at 100 degrees C, and evaluating the level of oxidation present. The many chemicals in the additive package-boron, barium, calcium, magnesium, molybdenum, sodium, phosphorous, sulfur, and zinc-are tracked, but these are not good indicators of the package’s remaining lifespan.

WearCheck offers three levels of analysis. A Level One basic check costs $15; Level Two adds Total Base Number, Total Acid Number, and metal-particle-count functions and costs $25; and Level Three includes high-end activities like direct-reading and analytical ferrography of metal particles, plus microscopic analysis of the engine’s actual oil-filter contents and is $100. A standard kit of a dozen 125-ml-capacity bottles, complete with forms, labels, and courier paperwork, sells for $180, which includes all analysis activity and the subsequent report.

Turnaround for a standard analysis is either same-day or, at the latest, next business day. Reports are typically sent by fax or e-mail-emergency conditions detected are telephoned at once-and clients can access a password-protected server over the Internet where the full history of all analyses for their entire fleet can be viewed and customized trend reports produced.

“Some clients have pushed drain intervals out to 80,000 kilometres with the use of by-pass filters,” Raymond notes. “However, we suggest that a client still sample at the same traditional 20,000- to 30,000-km interval. Tracking wear trends is a key benefit, and if you start skipping sampling periods or changing the intervals, your lab may detect developing problems too late to avoid component damage.”

Samples arrive each morning by courier from fleets across the country, and are opened, logged, and each bottle given a unique identifier code to maintain strict control while going through the analysis process.

If particulate matter is visible in the bottom of the sample bottle-this would typically come from a transmission or differential rather than an engine-most of that sample is decanted into another container while the particulate-laden portion is vacuum-filtered and taken for microscopic examination/identification (normal-wear-regime metal particles are less than 15 microns in size; pieces larger than this indicate severe wear).

The rest of the sample goes first to a “spatter test”-a hotplate set to 250 C onto which some drops of the sample are placed. If the liquid pops and crackles in reaction, there’s water in the oil. If so, the sample is run through a Karl Fischer titrator, which determines the amount of water, in parts per million (ppm).

The sample then goes to a plaso-spectrometer, where some is atomized and burnt in an argon flame. The resulting color-wavelength shows any presence of metals, antifreeze chemicals, or silica. If antifreeze (glycol) constituents are found, a colormetric test is run to more precisely determine the proportion.

Next comes a viscometer test, where oil is heated to 100 C to determine remaining viscosity in “centistokes.” After that, a BioRad infrared analyzer reveals levels of oxidation, soot load, sulphation, and nitration. Lastly, a gas chromatograph checks the oil sample for evidence of diesel-fuel contamination (detectable down to one-tenth of 1%).

“The results then go to one of our diagnosticians, who prepares the client report, complete with charts,” Raymond sums up. His lab averages 350 to 400 samples daily from all four client categories-maritime, aviation, industrial, and ground transportation-about 35% of which are truck fleets.

“Most of our 100-plus fleet customers just send crankcase samples,” he notes. “Some fleets also sample regularly from automatic transmissions, but for manual gearboxes or differentials you’ll likely only get a sample if they already think they have a problem.”

TESTING IN THE FIELD How do fleets feel about oil analysis? “I don’t think we’ve ever actually done a cost-benefit analysis,” says Norm Shupe, maintenance manager with Aldersyde, Alta.-based Mullen Trucking, who uses an Edmonton lab. “You just assume this is a desirable thing to do, especially when you start pushing out your drain intervals.” Mullen submits samples at every oil change, for every truck in the fleet, and also at the mid-point for the trucks on an 80,000-km drain schedule.

Mike Forest, service manager at Big Freight Systems in Steinbach, Man., reports that his fleet takes oil samples regularly, but not necessarily every oil change. They use two local labs.

“Almost all of our fleet is Cummins-powered, and they’ve created a matrix-type chart that gives guidance regarding extended oil-drain intervals,” he says. “We’ve now gone to 48,000-km intervals-and according to that matrix, we could go to 56,500 as long as we use a CH-4-Plus quality oil and demonstrate the desired fuel economy.

“For now, though, we’re quite comfortable with 48,000 km, and our oil-analysis program lets us be confident that our engines are handling that OK.”

Big Freight’s original change interval was 27,000 km, still used by about one-third of the company’s tractors because they pull heavily loaded Super-B trains and Forest feels this imposes enough strain on the engine lubrication system.

“One analysis report recently indicated abnormally high copper levels,” Forest recalls. “We checked the bottom half of that engine and found the babbitt lining for the bearings was uneven-a factory defect that was causing excessive bearing wear. If it hadn’t been for the oil analysis, we’d have probably lost that engine.”

On the other hand, one truck-leasing-firm maintenance manager reports that there’s an ongoing debate at his outfit as to whether to keep on doing regular oil analysis. “Can I honestly say that, in the 10 years I’ve been here, oil analysis has saved an engine for me?” he says. “No, I can’t. So far we’re still using it, and it is nice to get data for trend analysis for those trucks where we’ve pushed drain intervals out to double the normal recommendation.

“But, we have a big fleet, and every analysis costs about $13,” he sums up. “It’s hard to prove the economics one way or the other anymore.”