🔍 Key Concepts

• Trace the flow paths on the diagram for the lube oil coolers, gravity tank, and temperature control valve. • Identify what the gravity tank actually supplies and where its overflow line leads. • Understand how a three‑way temperature control valve normally regulates temperature in a lube oil system.

💭 Think About

• On the diagram, follow the lines connected to the lube oil coolers: do their drains really go to all three places listed in Choice A, or only some of them? • Look carefully at the gravity tank symbol: from its outlet and overflow connections, does it feed the turbines/gears continuously, or does it serve a different/backup purpose? • Find the three‑way valve near the lube oil cooler: is it drawn in the oil side or on the cooling‑water side, and what does that tell you about which medium it bypasses?

✅ Before You Answer

• Verify exactly where the gravity tank overflow line terminates on the drawing. • Confirm whether the normal supply to the turbines and gears comes from the main lube oil pumps or the gravity tank. • Check whether the three‑way valve is routing oil around/through the cooler or routing cooling water around/through the cooler – this is key to evaluating Choice D.