The highest indicated lube oil pressure in a...

Question 1 / 270705eccefa2bacbc34ba4d478eb

Question 1 of 270705eccefa2bacbc34ba4d478eb

The highest indicated lube oil pressure in a diesel engine should be expected when the engine oil is _________.

Question 1 of 27070

The highest indicated lube oil pressure in a diesel engine should be expected when the engine oil is _________.

🔍 Key Concepts

• Viscosity of lube oil vs. temperature (cold oil is thicker, warm/hot oil is thinner) • Effect of engine speed (RPM) on oil pump output and pressure • Fuel dilution and how thinning the oil changes indicated pressure

💭 Think About

• Think about when the oil is at its thickest and how that affects resistance to flow through bearings and passages. • Consider how idle vs. full speed changes the oil pump’s output and system pressure. • Ask yourself: when would the gauge show the highest back pressure in the system: thick oil or thin oil? Low pump output or high pump output?

✅ Before You Answer

• Compare which choice has the highest viscosity (cold vs. warm, diluted vs. not diluted). • Compare which condition gives the highest pump output (idle vs. full speed). • Eliminate any option where the oil would be thinned out (by temperature or dilution), since that tends to lower indicated pressure.

Question 1 of 27070

The highest indicated lube oil pressure in a diesel engine should be expected when the engine oil is _________.

cold at idle

warm at idle

warm at full speed

warm at full speed and no fuel dilution exists