What are the 3 types of hydraulic contamination?

• A. Gases and liquids
• B. Organic contamination only
• C. Dust, rust, oil
• D. Organic, Inorganic, and Metallic solids

Answer: (D)

Contamination in hydraulic systems is categorized by the type of solids present in the fluid. The three categories are organic solids, inorganic solids, and metallic solids. Organic solids come from degraded oil and varnish or deposits formed by oil aging and seals breaking down. Inorganic solids come from dirt, dust, silica, and mineral contaminants that ingress into the system. Metallic solids are wear particles from metal components, such as fragments from bearings, gears, or housings.

This breakdown is useful because each type points to different sources and maintenance actions: organic contamination often indicates oil quality issues or varnish formation, inorganic contamination points to leaks or poor sealing and ingress, and metallic contamination signals component wear and potential damage. Filtration and cleanliness strategies are then tailored to remove these particles effectively and to monitor system health.

Other options either mix different states of contamination (gases or liquids) or give incomplete or unrelated items, so they don’t align with this common way of classifying hydraulic contamination.