🔍 Key Concepts

• Hydraulic fluid contamination sources in machinery systems • Difference between solid particle contaminants and chemical contaminants • How oxidation changes the chemistry of oil over time

💭 Think About

• Which option describes something that chemically changes the fluid itself, rather than just being something mixed into it? • Look for the choice that most closely relates to aging or breakdown of the oil during normal service. • Ask yourself: which items are usually considered physical/particulate contamination, and which is a result of chemical reaction inside the fluid?

✅ Before You Answer

• Identify which answers are solid particles versus chemical compounds formed in the oil. • Consider what happens to hydraulic oil when it is exposed to heat, air (oxygen), and long service time. • Verify which option represents a degradation product of the oil rather than an intentionally added ingredient or external debris.