One of the main functions of oil analysis is to monitor levels of contaminants in the lubricating oil. Contaminants can be classed as being either internal or external. Internal contaminants are generated within the mechanical system such as wear debris or combustion by-products that accumulate in an engine oils as a result of burning diesel. External contaminants are substances that exist in the environment that should not be in the oil like airborne dust or water contamination. Contaminants can be directly damaging to the machinery being lubricated; dust is abrasive and can cause components to wear abnormally; water causes metals to rust. Contaminants can also cause the lubricating oil to degrade which in turn may have an adverse effect on a mechanical system been lubricated. When it comes to the analysis of used engine oils for condition monitoring purposes, certain contaminants are vitally important to monitor as they are often the root causes of premature oil degradation and engine failure. Several global engine manufacturers acknowledge the importance of monitoring equipment to improve reliability and reduce costs and one of the most effective and least expensive condition-monitoring techniques available to engine operators is oil analysis as it provides a wealth of information about the lubricant’s condition, contaminants and the mechanical wear taking place. This paper will look at the role oil analysis can play in engine reliability as well as describe the contaminants that are capable of causing premature or even sudden engine failure.

Steven Lara-Lee Lumley is the technical manager of WearCheck. She holds a NTC N6 diploma as well as Honeywell aerospace and ICML II accreditations and has 24 years of experience in oil analysis and asset management. Her portfolio includes oil analysis training and R&D of new products and services with a special interest in renewable energy technologies.