🔍 Key Concepts

• Diesel engine crankcase construction and normal flow paths (what is supposed to go in and out) • Sources of water in engine systems: cooling water, lube oil system, combustion products (blow‑by) • What each listed component actually carries: air, oil mist, combustion gases, or coolant

💭 Think About

• For each option, ask yourself: does this path normally carry LIQUID water into the crankcase while the engine is running? • Think about how blow‑by gets into the crankcase—what is blow‑by made of, and in what state (liquid vs vapor)? • Consider which of these systems is directly connected to the crankcase in a way that could introduce water if something went wrong or under certain load/temperature conditions.

✅ Before You Answer

• Be clear on what the crankcase exhauster actually does (direction of flow and what it removes). • Recall that demulsifying lube oil means oil that separates from water, not one that carries more water into bearings. • Decide whether condensation from an expansion tank can realistically form and then travel into the crankcase during normal operation.