CASTROL LABCHECK / Post date: 1 August 2017
Submitting complete and accurate oil sample information allows laboratory analysts to provide complete and accurate interpretation of the test results with well-informed and actionable maintenance or diagnostic recommendations.
Frequently, an oil sample arrives at the lab with only a unit ID and an indication that the oil is from a diesel engine. In such cases, only the most basic evaluation of the data can be performed and will likely be of little value as a predictive tool to the end user.
Things such as engine manufacturer and model, the total time on the unit, the amount of time the oil has been in service, the oil brand, type and weight, sump capacity, amount of oil consumption between preventative maintenance (PM) events, the engine’s application, and even geographical location are all major factors in determining the condition of both the oil and the component.
The following scenario illustrates one of numerous ways in which mechanical problems may go undetected, which can result in costly, unnecessary damage… simply because incomplete or inaccurate sample information was submitted with the oil sample.
Let’s say that your normal procedure is to collect an engine oil sample for an on-road truck at each PM interval and that interval is every 10,000 miles. Over a period of six submitted samples, the data consistently reveals the presence of approximately 80 ppm of iron, indicating a normal and predictable rate of wear. But at 1,500 miles after the latest PM, the operator reports an unusual noise coming from the engine. The unit is pulled from service and an oil sample is taken and submitted to the laboratory to determine the cause of the noise, but the unusually short time the oil has been in service is not reported.
After testing, the data indicated the presence of approximately 80 ppm of iron… as has been typical. Given the lack of data provided to the laboratory, nothing seemed unusual since that level of iron is consistent with prior samples. However, the iron, which was normally accumulating at a rate of approximately 0.008 ppm/hour, increased to an accumulation rate of 0.053 ppm/hour… over 500% of its historical value.
Without knowing the time that the oil was in service had been reduced to only 1,500 miles, the 80 ppm of iron appeared consistent and typical and the oil analysis report stated that the component condition appeared “normal.” The truck was placed back into service, but the unusual noise persisted and shortly thereafter the engine failed. An engine teardown and inspection revealed that a cylinder liner had developed a crack, which rapidly worsened over a short period of time. This eventually caused engine failure, as well as damage to the piston and rings.
If the recent in-service time of the oil had been reported to the lab, it would have likely been recognized that the iron level was critically high for just 1,500 miles in service. The resulting recommendation would have been to inspect the cylinders and/or other typical components made of iron.
If the damaged cylinder liner had been discovered and replaced at the first sign of an unusual increase in wear metals, it is much more likely that a costly, catastrophic failure could have been prevented. A small detail, like the amount of time on the oil, would have likely been the difference between an inexpensive part replacement and a very expensive catastrophic engine failure.
Importantly, the data that you provide to the lab can be equally or even more important than the data that the lab provides to you. This scenario is but one of many examples of potentially serious ramifications that can result from the lab not receiving complete and accurate information.
Always be sure to provide all of the information that the lab requests, as well as all other information that could be significant, such as operational problems, unusual noises, part replacements, notification of a recent overhaul, etc.