The viscosity rating of an oil indicates the

• A. Low temperature resistance
• B. Oils resistance to flow
• C. Ability to resist oxidation
• D. Temperature range of operation

Answer: (B)

Viscosity rating tells you how much the oil resists flowing. It’s a measure of how thick the oil is at a given temperature, so a higher viscosity means the oil flows more slowly and forms a thicker lubricating film, while a lower viscosity flows more easily. This rating helps predict how well a lubricating film will protect parts under load and at temperature, and it’s defined at standard temperatures. It doesn’t describe how well the oil resists oxidation or strictly define the engine’s usable temperature range, though viscosity does influence those aspects in practice. The essential point is that the viscosity rating indicates the oil’s resistance to flow.