Using On-Site Oil Analysis to Avoid Engine Failure and Optimizing Maintenance Schedules for Public Transport

Based in Bremerton, Washington, Kitsap Transit is a public transportation agency that operates a foot ferry service, routed bus service, and also provides service for disabled and elderly passengers in the Kitsap county. The agency has a fleet of about 362 vehicles, including cutaway small buses, transit buses, three passenger only ferries, and vans. As a result, preventative measures, such as elimination of engine failures and optimized maintenance schedules, have long been a major concern for the agency.

Earlier, Kitsap Transit’s maintenance department used to track the status of the engines by analyzing oil samples with the help of an external laboratory. Such analyses helped in determining radiator fluid and fuel contamination, heavy metal content, and so on. However, this process involves a significant amount of cost and time, where each sample costs as much as $40 when a third-party lab is involved, and it takes two to three weeks to obtain the results. The high cost restricts the number of samples that can be tested, and the long lead time means that a failure may occur even before the results could be obtained.

Spectro Scientific’s Solution

To resolve such issues, Kitsap Transit selected Spectro Scientific’s OSA4 TruckCheck® automated oil analysis system in 2014. With the help of this instrument, the agency’s maintenance department is now able to do on-site testing of oil samples, including total base number (TBN) results, within a matter of minutes for less than $1 per sample. Earlier, such a process could only be performed in the lab.

Griffey, who serves as a maintenance supervisor at Kitsap Transit, stated that in house oil analysis allows the agency to test all the bus engines frequently. In a span of a few months, the OSA4 analyzer successfully detected a couple of engines which were about to fail in the near future. This saved the agency approximately $40,000, as it prevented the necessity for an out-of-frame rebuild in one case, and in the other case, the rebuild was done as part of the warranty.

Kitsap Transit operates 43 ferry service and bus routes from Bremerton to Port Orchard in Washington. Its ACCESS service offers both curb-to-curb and door-to-door service for disabled and elderly passengers. The agency operates 32 worker and driver commuter routes to and from the Puget Sound Naval Shipyard and Naval Base Kitsap/Bremerton, where the drivers are employed as full-time shipyard workers. The fleet comprises of two 2003 ElDorado, nine 2012 Arboc, 11 g-4500s in ACCESS service, 17 2010 Arboc, 42 MCI worker/driver coaches from the 1990s, 45 Gillig models from the 2000s, 50 e-350 and e-450s, 124 vanpool and vanlink vans and a variety of trucks and cars (Figure 1).

Kitsap Transit has approximately 150 buses in its fleet.

Figure 1. Kitsap Transit has approximately 150 buses in its fleet.

Griffey added that Kitsap Transit is well aware of the potential benefits of oil analysis to reduce repair and replacement expenses and improve uptime, but since the agency could only perform infrequent spot checks on the engine oil, most of its benefits were missed out on. Oil analysis helps in determining the amount of different metals present in the oil, and makes it possible to estimate the extent of internal wear. Moreover, oil analysis determines the oil condition by quantifying the solids produced by oxidation, and by measuring the oil viscosity. Oil condition monitoring reduces the risk of major failure, and also reduces the expenses involved in changing and disposing of oil in heavy equipment.

Kitsap Transit works on a fleet schedule which includes an in-frame rebuild every 300,000 miles. In this rebuild process, the block is not removed from the frame when it is rebuilt. In this approach, the rods, pistons, and rings are replaced, and the spinning components are left untouched. For an out-of-frame rebuild, the block is removed from the frame and the crankshaft, camshaft, pistons, valve lifters, rings and rods are replaced. The costs involved in an in-frame rebuild can range anywhere between $13,000 and $25,000 for the buses, while the cost for an out-of-frame rebuild is twice the amount for an in-frame rebuild. In majority of cases, an in-frame rebuild is adequate, while an out-of-frame rebuild is necessary during engine failure.

Technicians Trained to Use Oil Analyzer in Two Hours

Griffey said that the automated TruckCheck oil analysis system was initially seen at a trade show, and Kitsap Transit was impressed with the reasonable cost of the system. With the help this instrument, they could prevent engine failures and thus eliminate the need for two out-of-frame rebuilds. The instrument was eventually purchased after cost assessments. Technicians at Kitsap underwent a two-hour course which allowed them to handle the system and carry out oil analysis.

As a tandem spectrometer, the TruckCheck analyzer combines an infrared module and an optical emission spectrometer (OES). The OES activates a part of the used oil sample, and ultimately determines the concentration of sub- microscopic metals present in the solution. These metals are present because of normal and abnormal wear of components. The infrared module is capable of scanning a part of the used oil sample to determine the physical characteristics of the oil, and to detect contaminants. Both spectrometers are controlled through an onboard computer, which records the results collected from each metal, including data about the vehicle and oil supplied by the operator. A report created by the software comprises of the test results and a diagnostic statement which notifies the operator in case the results are found to be beyond the normal ranges. Technicians at Kitsap Transit are now able to carry out oil analysis on a routine basis whenever there is a need to change the bus engine oil (Figure 2).

Technicians obtain oil analysis results in less than 15 minutes.

Figure 2. Technicians obtain oil analysis results in less than 15 minutes.

Bill Rich, who works as a lead mechanic at Kitsap Transit, said that the oil used at Kitsap Transit did not meet the V100 or V40 specification even soon after changing the oil. It was also found that an extra 10 points are being lost on the V40 specification over the lifespan of the oil. Since running the engines with a low viscosity resulted in engine wear, the agency switched to a new oil supplier. Now, oil monitoring is done with each and every change to ensure that the oil meets the desired specification.

Costs Saved BY Avoiding Out-of-Frame Overhaul

Rich added that when a mid-size Cummins diesel engine was tested, the level of heavy metals found was high. This engine was not meant to be rebuilt for the next 11 months, and hence, would have possibly failed before that period. In such a scenario, the spinning parts would have broken down and an out-of-frame overhaul would have been neccessary for the engine, all of which would have amounted to around $15,000. However, early detection of the problem helped the agency to save half the cost of the oil analyzer.

In yet another example, a bus fitted with a Detroit Diesel Series 60 engine was taken in for maintenance purposes as the oil was overfull. Earlier, oil analysis would not have been carried out, but now such analysis is performed regularly on engines brought into the shop. In this application, oil analysis revealed that the overfill was the result of diesel fuel entering the oil. The engine would have probably failed as it close to the warranty period, which would have made neccessary another out-of-frame overhaul at a cost of around $25,000. Instead, the results were sent to the dealer, who fixed the issue without any cost to the agency.

Heavy fuel dilution was also detected by the TruckCheck analyzer, which indicated untimely wear on engines integrated in compact cutaway buses. At some point in time, these engines would have failed, and by the time this occurred, they would have reached their warranty expiration period, necessitating an out-of-frame overhaul. Kitsap Transit has teamed up with the bus dealer to overcome such problems, which will all be covered under the warranty. In view of the considerable cost of performing an out-of-frame overhaul on the engines, the potential savings are noteworthy.

Griffey further added that the OSA4 automated analyzer was mainly purchased for their bus engines, but the system is now also being used for other applications. For example, when a bus with low power steering fluid was brought into the shop, the technician tested the steering fluid and detected large amounts of iron, which was traced to the pump. This pump was subsequently replaced, which solved the issue. The analyzer is also being used to check the engine oil in Kitsap Transit’s three ferries. Since there were just three ships, even if one ship failed, it would result in a major issue. Although no such issues have been encountered, the agency is more confident about its ferry service because it can now easily detect the issues before any failure actually occurs. Kitsap Transit is also inspecting the transmission fluid of the fleet, which will translate into more savings.


Overall, the investment made on Spectro Scientific’s OSA4 TruckCheck® automated oil analysis system has been recovered by the agency within a matter of few months. The agency is also exploring potential areas where it can save money and realize optimum usage of its fleet.

This information has been sourced, reviewed and adapted from materials provided by AMETEK Spectro Scientific.

For more information on this source, please visit AMETEK Spectro Scientific.



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