🔍 Key Concepts

• Pressure relationship between sea water side and jacket water side in a cooler to prevent contamination of the engine’s closed loop • What happens to fluid flow direction through a leak when two systems are at different pressures • Purpose and behavior of the jacket water expansion tank level in a closed cooling system

💭 Think About

• If a leak develops between the sea water and jacket water sides, which fluid do you want to be forced into the other, and why (think corrosion, contamination, and engine protection)? • In a closed fresh water (jacket water) system with an expansion tank, what happens to the tank level if fresh water is lost from the system during operation? • If sea water entered the jacket water system instead, how would that affect the expansion tank level: would it rise or fall?

✅ Before You Answer

• Decide which side should be kept at higher pressure under normal operation to protect the engine’s closed cooling system from sea water contamination. • Determine whether a leak at the cooler would cause the expansion tank level to increase or decrease, based on which fluid is entering or leaving the jacket water side. • Verify that your chosen option matches both the correct pressure relationship and the correct expansion tank level change.