🔍 Key Concepts

• Fuel dilution in lube oil and how it happens in diesel engines • What happens when fuel injection timing or spray pattern is incorrect • How compression and incomplete combustion can affect unburned fuel in the cylinder

💭 Think About

• For each choice (A, B, C), ask yourself: Could this condition allow more unburned fuel to reach the cylinder walls and slip past the rings into the crankcase? • Think about how a leaking injector, poor compression, or delayed injection would change the burning of fuel inside the cylinder. • Consider whether more than one of these conditions could exist at the same time and all contribute to the same problem.

✅ Before You Answer

• For each option, mentally trace the path: from injector → combustion in cylinder → fuel on cylinder walls → past piston rings → into crankcase oil. • Verify which conditions would increase unburned liquid fuel in the cylinder at the end of the power stroke. • Before picking D (All of the above), be sure that every single listed condition can reasonably lead to extra fuel getting into the lube oil.