Question 189Motor Plants - QMED

The correct answer is D) Cylinder lubricating oil. When oil discharges are detected during the blowing of scavenging air receiver drains on a slow-speed, two-stroke, turbocharged, aftercooled engine, the most likely source is the cylinder lubricating oil. This is because the cylinder lubricating oil is injected directly into the engine's cylinders, and any excess oil can be swept out during the scavenging process, leading to the observed oil discharges. The other options (turbocharger lubricating oil, crosshead lubricating oil, and bearing lubricating oil) are less likely sources, as these oils are used in different parts of the engine and are not directly involved in the cylinder scavenging process.