Understanding used oil analysis
Darryl Purificati, OEM technical liaison at Petro-Canada Lubricants, explains the analysis process and how to interpret the results
Lubricants are the lifeblood of any engine – they have a greater effect on an engine’s health and longevity than anything else. Working to fight against an engine’s two biggest challenges, heat and friction, heavy-duty engine oil has a vital role to play in preserving engine life.
Ensuring that the condition of the oil is optimal is critical in maintaining engine longevity. Used oil analysis is an engine’s preventative medicine – a tool to monitor and identify any potential concerns or issues with the overall health of operation.
As a proactive maintenance measure, used oil analysis can also highlight and identify the signs of mechanical failure within the engine before it becomes too serious or expensive to repair.
The data provided in a used oil analysis report can also offer operators the potential to extend oil drain intervals*, providing another effective method for reducing maintenance costs and increasing fleet time on the road.
There are three simple steps to used oil analysis.
1.Taking a representative sample
This is a critical step in the process, as improper sampling can lead to inaccurate interpretation of the results and potential equipment damage or failure. A clean, dry container suitable for holding used oil should be used, with a label affixed to it that has the information for the laboratory to put into their database, for example equipment type and miles/hours of operation.
Before taking the sample, the sampling point should be clean, and a small amount of oil should be flushed to ensure that no foreign contaminants make their way into the bottle.
2.Sending the sample to a qualified used oil analysis laboratory
Once the sample has been taken, it should be sent as soon as possible to a certified oil analysis laboratory. In some cases, a delay can mean the difference between being able to diagnose and correct a serious condition and losing a critical piece of equipment due to failure. The laboratory will then test the oil using standard test regimes, providing accurate results and diagnosis in a report.
3.Interpreting and acting upon the report results
To effectively interpret the results for your equipment, it is key to have guidelines on what levels are normal for your type of machine and how it operates, as looking at the trends over time provides more insight than single values.
When working with a specialised oil provider, or technical service advisor, experts will be on hand to provide analysis and highlight significant changes in the report’s findings. As part of this process, they will evaluate the trends that have developed over time and highlight any anomalies along with recommendations for maintenance, and if it is possible, to even extend oil drain intervals.
It’s also valuable for fleet owners and operators to be confident in interpreting used oil analysis results and correctly identify their causes. The maintenance team will then become familiar with a ‘normal’ reading for their fleets as well as ensuring that any required maintenance is organised as quickly as possible before further problems arise.
Fleet owners and their teams know their equipment and the demands they make of it. They are best placed to anticipate when it will be under additional pressure and needs to be operating at maximum capacity. By understanding how to analyse the reports, trends and anomalies in results can be identified quickly and maintenance schedules updated as required, in line with commercial demands.
When first reviewing a used oil analysis report it is important to look at many of the key indicators, like base number (BN), acid number (AN), viscosity, oxidation, fuel soot per cent and fuel dilution per cent as well as wear metals.
Also, the presence of glycol or coolant, which would be shown through increases in silicon, potassium and/or sodium, and potentially water, can be the first signs of a failing Exhaust Gas Recirculation (EGR) cooler seal, so would require the immediate attention of a technician or mechanic.
Increases in iron and aluminium can mean that a component within the engine is abnormally wearing at an accelerated rate. This could potentially be a failing camshaft, coolant leak attacking the liners or the engine requiring mechanical adjustment, so spotting the signs early could result in significant cost and maintenance savings.
If iron, aluminium, lead and copper have all increased, the protection of vital engine components may have been compromised, so expert support should be sought to help resolve the issue.
Monitoring the levels of key properties within the engine oil provides fleet owners and operators with the ability to predict issues and schedule maintenance before problems become too expensive or serious to repair.
Effectively helping reduce the risk of unplanned downtime and sudden engine failures, used oil analysis and data interpretation can reveal how abnormal metal to metal contact has accelerated and help identify its cause.
* Extending drain intervals should always be undertaken in conjunction with an oil analysis programme.
