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The reasons that lubricants age and need to be replaced periodically are well known. It is true that many of the factors that influence lubricant consumption and oil change intervals are not within the realm of control of most users. However, there are far more controllable factors that many user organizations fail to capitalize on in reducing both costs and risks associated with relubrication.
According to one report, the true cost of an oil change can exceed 40 times the cost of the oil itself. In fact, there are many hidden costs and unknown risks that are encountered during relubrication that must be considered. Let’s look at some of the risks in doing a simple oil change:
When you look collectively at the true cost of an oil change and the associated risks, there is an abundance of financial and business motivation to maximize, or at least optimize, the oil change interval. When well implemented, this can translate to sharply reduced oil consumption, lower maintenance costs and greater machine reliability.
Let’s begin by examining the need for an oil change. Oil doesn’t last forever; it ages in ways similar to the human body. By exposing a lubricant to the elements within a machine (heat, air, water, glycol, particulates, shear, etc.), irreparable damage is often done. Additives can extend a lubricant’s life, but they can’t prevent degradation and aging altogether. Lubricating oils need to be changed for the following reasons:
The following are several common and a few not-so-common methods for reducing lubricant consumption and extending drain intervals. Not all of these methods have practical application in every case where lubricants are used. However, in those cases where extended drain intervals have the greatest potential benefit, a strategy for success relating to the methods can usually be constructed.
There are a great many differences in the durability of lubricants when exposed to machine operating conditions. Therefore, one simplistic strategy is to select lubricants with robust formulations that resist degradation in the target application. The use of high-purity mineral oils, oxidatively stable synthetics, enhanced antioxidant systems, better demulsifiers, robust over-base additives and long-life dispersants can substantially extend service life of the lubricant. Additionally, select lubricants for the applications for which they were formulated. For instance, a high-performance motor oil might exhibit superior performance in a diesel engine, but it might fail rapidly when used in a hydraulic system.
Most additives deplete at a rate proportional to the density of exposure to a range of contaminants and operating conditions. Water, dirt, metal particles, soot, heat, acids and air are all contaminants that put stress on additives and lead to their depletion. Additive depletion is the usual precursor to base oil failure, impaired machine performance and eventual machine failure. The following are examples of how to reduce exposure density:
Depleted additives can be restored in a couple of different ways for the purpose of extending the oil change interval and to avoid the wasteful disposal of otherwise healthy oil. These are the two options available to users’ organizations:
A vast amount of lubricant is wasted each year due to premature and unnecessary oil changes. In fact, the life expectancy of a lubricant cannot be accurately predicted due to the numerous factors that both induce aging and resist aging. No lubrication expert or computer program can forecast the need for an oil change. Therefore, users are faced with either changing the oil well in advance of any expected end-of-life oil condition (a wasteful and risky practice) or to periodically analyze the oil to monitor the advancing end of life (a far better practice). Analyzing the oil using routine oil analysis is a far more practical and reliable alternative.
Of course, leakage doesn’t actually trigger the need for an oil change, but it certainly does result in unnecessary oil consumption through repeated addition of make-up oil. Fortunately, healthy, uncontaminated oil can have an amazing positive impact on reducing oil leakage. Likewise, leakage is often associated with excessive contaminant ingression, which, of course, shortens oil life. All told, there are many opportunities to reduce oil change frequency and the associated costs and risks. All of these involve some form of intervention, transforming past practices to oil-life-extending new practices. Precision lubrication is about selecting the correct intervention action(s) to systematically achieve the intended objective at the lowest possible cost and risk to the organization. In this case, lower oil consumption by extending oil drain intervals.