Detergent additives in oils are used to do what?

• A. To color the oil
• B. To decrease viscosity
• C. To reduce flash point
• D. To break up and wash away deposits

Answer: (D)

Detergent additives in lubricating oils are there to keep engine parts clean by controlling deposits. They work by keeping impurities and oxidation byproducts dissolved or suspended in the oil, rather than letting them stick to metal surfaces. This lets existing varnish and sludge break up and be carried away with oil circulation to the filter or during an oil change, while preventing new deposits from forming on pistons, valves, and bearings. They aren’t intended to color the oil, change its viscosity, or alter the oil’s flash point.