Question 49 DDE01 - Designated Duty Engineer - Unlimited HP

The Correct Answer is B **Explanation for B (4):** Item number 4 points to the pump that is located immediately downstream (after) the main engine's bearings and sumps. In large engine lubricating oil systems, especially those using a dry sump design common in marine propulsion, the **scavenging lube oil pump** (also called the return pump) is responsible for drawing the used oil out of the engine's sump or drain pan and pumping it back to the settling tank or storage tank (Item 12) for cooling (Item 9) and filtration (Item 2) before it is reused by the main pressure pump (Item 6). Item 4 is clearly positioned to perform this return function. **Why other options are incorrect:** * **A) 2:** Item number 2 represents the **lube oil filter** (or strainer). This component cleans the oil before it is sent to the engine bearings by the pressure pump (6). * **C) 9:** Item number 9 represents the **lube oil cooler**. This component removes heat from the lubricating oil before it is delivered to the engine. * **D) 12:** Item number 12 represents the **lube oil storage/settling tank**. This is where the oil is held and allowed to settle impurities (like water or sludge) before being drawn into the system. It is not a pump.