🔍 Key Concepts

• Heat exchanger operation in a lube oil cooler (which side is more critical to protect: lube oil or sea water?) • Relationship between pressure difference and leak direction in a cooler • Effect of a leak on lube oil sump level depending on which fluid is entering or leaving

💭 Think About

• If there is a leak in the cooler, which fluid do engineers most want to keep OUT of the other system: sea water in oil, or oil in sea water? Why? • If the higher-pressure fluid leaks into the lower-pressure side, what happens to the lube oil sump level in each possible case? • Think about contamination: which is more dangerous for the engine—sea water getting into lube oil, or a little oil lost to sea water?

✅ Before You Answer

• Decide which side should be kept at higher pressure to minimize damage from a leak. • Trace the flow in a leak: does lube oil go to sea water, or sea water to lube oil, under that pressure condition? • From that leak direction, determine whether the lube oil sump level would rise or fall.