Water is one of the most destructive contaminants of oil. Water attacks
additives, generates oxidation and modifies the vapor pressure of oil; it corrodes metal surfaces, facilitates emulsions, blocks filters and hinders in the formation of the protective film. Water increases dramatically the corrosive potential of acids present in oil. In diesel engines, light
contamination is normal, however, critical to certain hydraulic equipment and compressors. Severe contamination deserves close attention and will seldom be suppressed with an oil change.