While oil analysis can help our teams identify more information about the condition of the oil, we still need to ensure that they can read the oil analysis report and put measures in place to deal with the issues which may arise. In the example below, we will look through a typical diesel engine report as provided by ALS Tribology lab featured in STLE’s TLT magazine as shown in Figure 1.
Most labs try to make it very easy for the report readers to assess the health of the oil, at a first glance. They usually implement a traffic light system where the status of the oil is highlighted. In this case, this oil has a normal rating indicating that the oil is still in good health and there isn’t anything to be concerned about yet as shown in Figure 2.
However, one of the main premises of oil analysis is the ability to spot trends over time and from this report, we can see that the oil may not have always been in a good condition as shown in figure 3. Each column represents an oil sample from a different date, so at a quick glance we can see that for two of the results, the oil was not in a good state whereas for the other results they remained in the normal region.
One question that often gets asked is, “What is the normal region?”. Most oil analysis labs have collected data from OEMs which explicitly state the alarm limits for their pieces of equipment. As such, for each component, a lab should have matching data for alarm limits for the oil in that component. If none exists, then the lab may use a general industry guideline for these limits.
Therefore, if the actual value of the oil either exceeds or is below the limit, then this value will be flagged and the user notified. As seen in the report, there are basic sections into which these values are broken up, namely; metals, contaminants, additives and physical tests. Depending on the OEM, there will be different limits for these values.
However, our teams need to be able to identify what the presence or absence of the elements mean for different components.(Bureau Veritas, 2020) compiled a listing to help report readers understand this better as seen below.
Armed with this information, our teams can make more informed decisions. If they start seeing the quantity of Chromium increasing in their engines then this could be a sign of wear on the Liners and rings, shafts, valve train, bearings, shafts and gears, seals. Therefore, some investigations can begin on these components and possible wear can be addressed before the component gets damaged to the point that it can no longer function. Similarly, if they notice particular additives decrease over time such as zinc, then this could indicate that the antiwear additive is being depleted at a faster rate. These tables can guide report readers on what is actually occurring in their oils allowing them to properly plan for maintenance activities.
