The Factors That Affect Results

Oil analysis results are shown in Parts Per Million (PPM) for each element, or how many particles of the specific element metal are found per each million parts of oil. This absolute value is obviously affected by the amount of specific metal generated by engine wear per hour, and the number of hours the engine has been run for this oil sample. Newly built or overhauled engines are expected to have a high amount of wear initially, and this will normally decrease over time after break-in. Of course a six cylinder engine has more moving parts than a four cylinder engine, and thus can be expected to generate more wear metal per hour of operation. Engine size is also a factor for the same reason. Other factors include how many hours has it been since the engine oil was changed, and how much residual wear metal remained suspended within the engine when the old oil was removed.

One can easily understand this last interaction by visualizing the simplified model of a leaky milk jug suspended over a glass of water. The milk jug represents the engine creating wear metal (milk) droplets at a generally constant rate per hour. The glass of water represents the engine oil which gets contaminated over time by the milk droplets and turns cloudy. It is quickly obvious that the amount of dripping time and the amount of time passed since last dumping the glass and refilling with fresh water will determine the cloudiness at any instant. The amount of cloudiness at any instant can be measured in PPM of milk. When you dump the glass of water, you will remove most of the milk, but a residue will always remain, depending on the smoothness of the glass. This residue will determine a starting point PPM. If the glass also held some marbles, thereby increasing the interior surface area, then even more milk residue would remain. Once you consider the numerous oil passages, bearing surfaces, and crannies in your engine, you will quickly realize that a substantial amount of wear metals will remain after the old oil is drained. This affects future PPM measurement, however the effect diminishes with time. But just how much and when?

The bottom line is that for proper evaluation of oil sample analysis results, one can not simply look at the measured PPM value and make any valid judgment at all. The engine model, cylinder type, time since overhaul (or new), and oil hours must be factored in. Nor can "average" values be used as purported by other oil analysis companies. Your specific factors must be used and compared to a sufficiently large sample size, historical population of same engine model, same cylinder type, similar time since overhaul, and similar oil hours. These selected historical samples will uniquely determine the data points for each engine oil sample that will properly determine if your engine oil sample analysis values are abnormal or any cause for concern.

Also curious as to why they switched from the FL1A filter to the 820S?