🔍 Key Concepts
• Follow the lube oil flow path from the sump and pump to the engine and see which cooler it passes through.
• Distinguish between jacket (fresh) water cooling, piston/charge air cooling, and lube oil cooling based on where they connect on the engine.
• Note which side of each small heat exchanger (3, 4, 5, 6) is connected to the central fresh‑water cooling circuit and which side is connected to another fluid (fuel, LO, etc.).
💭 Think About
• Starting at the lube oil sump and lube oil pump symbols, which numbered heat exchanger does that line go through just before the oil enters the engine?
• Which of the exchangers 3, 4, 5, 6 has one side clearly on the lube oil system and the other side on the engine cooling water system?
• Can you eliminate any of the options by recognizing a fuel oil heater or a jacket water cooler, based on their connections and positions?
✅ Before You Answer
• Verify the lube oil pump symbol and label and trace that specific piping only.
• Confirm that the chosen heat exchanger has two different media: one side tied into the lube oil system, the other into the cooling water system.
• Double‑check that the remaining exchangers (from choices not selected) are serving other systems such as fuel conditioning or jacket water, not lube oil.