Lube Oil - MCQs Quiz

What is the primary function of lube oil in a diesel engine?

• To cool the engine exhaust

• To reduce wear and remove contaminants

• To increase combustion temperature

• To supply fuel to injectors

In hydrodynamic lubrication, how is the oil film formed?

• By external pressure from a pump

• By adhesive properties of oil

• By the motion and self-generated pressure of moving parts

• By temperature gradients

What is the effect of fuel contamination in lube oil?

• Increases viscosity

• Improves oil film strength

• Reduces viscosity and flash point

• Enhances cooling performance

What is the maximum allowable water content in lube oil for a trunk type engine?

• 0.5%

• 1.0%

• 0.2%

• 0.1%

What does TBN (Total Base Number) indicate in lube oil?

• Acid level in the oil

• Oil viscosity

• Alkalinity or neutralizing capacity

• Water content

Which lube oil property measures its resistance to flow?

• Flash point

• Pour point

• Viscosity

• TAN

What happens if lube oil with low flash point is used?

• Causes oil thickening

• Reduces corrosion

• Increases the risk of fire or explosion

• Improves lubrication efficiency

What additive helps in preventing deposit formation in lube oil?

• Antifreeze

• Dispersant

• Detergent

• Stabilizer

What type of lubrication occurs during engine start-up and shutdown?

• Hydrodynamic

• Hydrostatic

• Boundary

• Elastohydrodynamic

Why is high viscosity index desirable in lube oil?

• Ensures thicker oil

• Indicates resistance to contamination

• Oil maintains consistent viscosity across temperatures

• Improves pour point