🔍 Key Concepts

• Oxidation of hydraulic oil when water is present • Effects of degraded/oxidized oil on system components (valves, pumps, actuators) • What filters can and cannot remove from a hydraulic system

💭 Think About

• When water mixes with hydraulic oil and oxidation occurs, what kinds of chemical changes typically happen to the oil? Think about whether they make the oil thicker, stickier, or more corrosive. • Consider what problems contaminated or oxidized oil can cause inside small clearances, control valves, and servo mechanisms. • Ask yourself: can normal particulate filters remove chemical breakdown products, or only solid particles of a certain size?

✅ Before You Answer

• Verify what typical oxidation by‑products of petroleum-based oils are called in maintenance manuals and tribology texts. • Check whether cellulose filters are designed to remove water, solids, or chemical compounds formed in the oil. • Confirm whether oxidation products are considered harmful to components (causing sticking, corrosion, loss of clearances) or truly harmless.