What term describes any material foreign to a hydraulic fluid that harms performance in a system?

• A. Contamination
• B. Excessive heat
• C. Improper fluid
• D. Over-pressurization

Answer: (A)

Contamination is anything foreign to the hydraulic fluid that can interfere with how the system runs. In a hydraulic system, clean fluid is essential because pumps, valves, and actuators rely on precise clearances and stable viscosity. When dirt, wear debris, rust, moisture, or air enter the fluid, they can clog filters, abrade surfaces, and cause seal and valve wear. This degrades performance, leads to erratic operation, overheating, and shortened component life. The other terms describe conditions or choices that affect performance but aren’t the presence of foreign material in the fluid itself. Contamination specifically captures the idea of unwanted material inside the fluid that harms the system.