What is a common indication of hydraulic fluid contamination?

Milky colored fluid is a key indicator of hydraulic fluid contamination, often due to the presence of water or emulsified substances within the hydraulic system. This milky appearance suggests that water has mixed with the oil, creating an emulsion that degrades the fluid's performance and can lead to operational issues within the hydraulic system. Contaminated hydraulic fluid not only diminishes the fluid's lubrication properties but can also affect the functioning of hydraulic components, resulting in reduced efficiency and potential damage.

Clear fluid typically indicates that the hydraulic oil is functioning properly and is free of contaminants. Bright colors can suggest the addition of dyes or other additives, but do not inherently indicate contamination. Bubble formation is often associated with entrainment of air within the fluid, which can occur from mechanical agitation or leaks, but does not specifically denote contamination in the same way that a milky appearance does. Thus, milky colored fluid serving as a clear sign of contamination demonstrates the critical role of monitoring hydraulic fluid quality in maintaining system performance and longevity.