🔍 Key Concepts

• relationship between temperature and viscosity of lubricating oil • difference between physical properties of oil (like viscosity) and chemical properties (like flash point and pour point) • effect of cooling on how easily oil flows and holds contaminants in suspension

💭 Think About

• Ask yourself: when oil gets colder, does it flow more easily or more slowly? Which property describes that behavior? • Which of the listed properties is MOST directly and immediately affected by a small change in temperature in normal operating ranges? • Which property is related to how well oil can keep particles suspended versus letting them settle out when the oil is cooled?

✅ Before You Answer

• Be clear on the definition of viscosity (how thick or thin a fluid is, or its resistance to flow). • Review what flash point and pour point actually mean and whether they change with small operating temperature changes. • Think about what happens in cold weather to engine oils: which of these properties is usually discussed when talking about cold start performance?