🔍 Key Concepts

• Cooling water circulation around cylinder heads in diesel engines • Effect of air pockets on heat transfer and metal temperature • Relationship between local overheating and engine damage or deposits

💭 Think About

• Think about what happens to metal surfaces if cooling water is blocked or partially missing in certain areas. • Which listed condition is the most direct and immediate result of poor heat transfer in the cylinder head? • Which options describe secondary effects that would normally take longer to develop or relate to a different system (like fuel or scale)?

✅ Before You Answer

• Identify which choice is directly caused by loss of cooling and poor heat transfer, not by changes in fuel properties. • Eliminate any options that concern fuel system characteristics rather than the cooling passages. • Consider which effect would show up first if an engine is run with air pockets in the cooling passages.