Water - An easy test under any circumstances.

Oil and water do not and really should not mix.  Water can be in the lubricant in a dissolved or free state and is one of the most common contaminants.  Sources of contamination include combustion, condensation, leakage, air bourn moisture, spray etc. The list is long.



On-Line – Water detection via sensors is usually accomplished by humidity measurement or infrared technology. As noted in the Tier Efficacy Chart water is very likely most accurately determined with a sensor, where the entire lubricant is the ‘sample’, therefore there is no issue with sample representation.

On-Site – There are numbers of ways to test for water, including

• Coarse verification (Yes or No): hot plate sputter test
• Chemical reaction in a ‘smart vessel’
• Portable infrared spectrometric devices

Off-Site – It is possible to determine water concentrations at ppm (parts-per-million) levels using Karl Fischer titration procedures. While this is clearly an accurate procedure, one needs to be wary of the exposure to possible errors that the sampling process can induce (e.g. inherent lack of sample homogeneity when mineral oils are involved).

Reporting Units: Water is usually reported in percentage or in ppm, dependent on the precision deemed necessary and the method used.



Above: bearing failures due to water contamination

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Discussion: Water is always undesirable in the lubricant, unless one is dealing with high water-base fluids for anti-flammability constraints as special exception. Water contamination can occur gradually or rapidly (unlike for example BN -formerly TBN -depletion which is quite slow). Controlling water is imperative, but it is easier said than done:

• Diesel engines produce a lot of water simply from their normal combustion cycle process. It is true that the crankcase temperature is high enough to evaporate virtually all of the water, however, you can imagine what happens when an engine is shut down for the day and condensation occurs as the engine’s temperature reverts to ambient

• In industrial application settings, water is frequently an issue with processes and washes

• In off-highway applications, equipment is exposed to the elements, and water becomes an issue there, as well

Suffice to say, the best form of control is to prevent the initial contamination.

• Use desiccant breathers when appropriate

• Use best practices to prevent contamination during storage and transfer