🔍 Key Concepts

• lubrication theory – how oil forms a film between moving metal surfaces • the purpose of different lube oil additives (friction vs cleaning vs temperature/pressure protection) • difference between additives that handle high load or pressure and those that handle sludge, acids, or corrosion

💭 Think About

• Which type of additive is specifically aimed at keeping metal surfaces from touching under heavy load, so friction and wear are reduced? • Which choices describe additives that mainly keep contaminants in suspension or control chemistry (like acidity/alkalinity) rather than directly reducing metal-to-metal contact? • Think about what happens in gear teeth or heavily loaded bearings – which additive name sounds designed for that situation?

✅ Before You Answer

• Match the additive name to its primary function: friction and wear reduction vs cleaning vs chemical control • Eliminate options that mostly relate to detergency/dispersion or pH control instead of boundary lubrication • Ask: under very high load where the oil film might break down, which additive would protect surfaces from scuffing and welding?