ABYC Diesel Practice Exam

If no water comes out when draining a seawater-cooled engine, what is the most likely issue?

1. The engine has run dry

2. It may be blocked, and a tool should be used to remove the blockage

3. The drain plug is missing

4. There is a leak in the cooling system

The correct answer is: It may be blocked, and a tool should be used to remove the blockage

When no water comes out when draining a seawater-cooled engine, the most probable issue is that there is a blockage in the cooling system. Seawater cooling systems rely on intake fittings, hoses, and various passages to circulate water effectively through the engine. Over time, debris, marine growth, or salt deposits can accumulate, leading to blockages that prevent the free flow of seawater. Using a tool to remove the blockage is an appropriate response as it addresses the root cause of the issue. By inspecting and clearing any obstructions, normal drainage can be restored, helping maintain the engine's cooling efficiency. Identifying and resolving blockages is crucial in seawater-cooled systems to prevent overheating and potential engine damage. Other options, while they discuss possible issues, do not directly address the immediate likelihood of encountering a blockage when no water is observed. For instance, while running dry could potentially happen, it's less likely to be the reason for no drainage specifically when the engine is still operational. Missing drain plugs or leaks would typically result in water loss rather than a total absence of drainage, making them less directly applicable in this scenario.