Question 336Motor Plants - Assistant Engineer

The correct answer is D) sea water. In the engine illustration MO-0003, the part labeled 'W' is typically the engine block or cylinder heads, which are cooled by a sea water cooling system. This is a common cooling method used in marine diesel engines to dissipate the heat generated during the combustion process. The other answer choices are incorrect because lube oil (A) is used to lubricate the engine, not directly cool it, convection (B) is a general heat transfer mechanism but not the specific cooling method for this engine component, and air (C) is not the primary cooling medium for this type of marine engine.