Establishing Testing Benchmarks

Normalising is applied only to results that increase with time due to wear. Finite caution limits for say water content, viscosity, silicon/aluminium content (dirt/sand) and fuel dilution are not normalised since the deviation from the normal analysed levels of these can be due to the introduction of external (ie not wearing) contaminants which when reached requires action to be taken irrespective of the time it has taken to exceed the levels.

Intervals need to be specified to compare “apples with apples” across the useful life of the equipment.

Oilcheck uses 200 hours or 10,000 kilometres as a standard on engines and 500 hours or 25,000 kilometres on all other compartments.

The results of each oil analysis are weighted proportionately to fit into the specified category to achieve a “normalised” set of data as shown in the table.

The corresponding graph compares “raw” and “normalised” data.

The “normalised” data is then compared with the standard deviations to determine the status of the oil.