Question 55 MODE01 - Chief MODU Engineer

The Correct Answer is C **Why Option C ("Leaking aftercooler") is correct:** The scavenging air receiver is located immediately after the turbocharger's compressor and the air cooler (aftercooler). The aftercooler's function is to lower the temperature of the compressed air using a cooling medium, typically seawater or fresh cooling water, which flows through tubes or plates. If the aftercooler develops a leak (e.g., a crack or perforation in a cooling tube), the cooling water will mix with the scavenging air. Since the air receiver is the next component, this water will be carried into and collect within the air receiver, where its presence indicates the failure of the cooler itself. **Why the other options are incorrect:** * **A) Excessively high scavenge air temperature:** High temperature is a result of inefficient cooling (or a fault like turbocharger surging) but does not introduce liquid water into the system. While a faulty cooler can cause high temperatures, the temperature itself is not the *source* of the collected water. * **B) Auxiliary blower failure:** Auxiliary blowers (used at low engine loads) assist in supplying air but do not introduce cooling water. Their failure would result in insufficient air pressure or flow, not water contamination. * **D) Leaking cylinder head gaskets:** Leaking cylinder head gaskets typically allow combustion gases or jacket cooling water to escape into the crankcase or the exhaust system, or potentially into an adjacent cylinder. They do not directly introduce water into the scavenging air receiver, which is located on the intake side, far upstream from the cylinder head.