🔍 Key Concepts

• Closed vs. open (raw) cooling circuits in a diesel engine • Where temperature is most critical for protecting the engine from overheating • The usual location of sensing bulbs/thermostats in jacket-water systems

💭 Think About

• Ask yourself: At what point in the cooling circuit does an excessively high temperature most directly indicate danger to the engine components themselves? • Which location measures the temperature of water that has just absorbed heat from the engine, rather than before it does? • Is the alarm intended to protect external equipment (like a heat exchanger) or the engine’s internal parts (cylinders, heads, liners)?

✅ Before You Answer

• Identify which answer choice corresponds to water that has just left the engine jackets after cooling the engine • Distinguish between raw (sea) water side and fresh (jacket) water side of the cooling system • Confirm where high temperature alarms are typically installed in standard medium-speed diesel jacket-water systems