🔍 Key Concepts

• Diesel engine valve train and how valves guide and seal moving parts • How lubricating oil can enter the combustion or exhaust path • The path from cylinder head/valves to the exhaust manifold

💭 Think About

• Which component listed actually has a direct path for oil to leak into the exhaust ports and then into the exhaust manifold? • Think about whether each option would tend to keep oil inside the crankcase, or allow it to migrate upward into the cylinder head and exhaust area. • Which condition would more likely cause oil leakage past a moving part rather than just changing oil pressure or crankcase conditions?

✅ Before You Answer

• Identify which choice is physically connected to the valve stem / cylinder head / exhaust port area. • Eliminate any options that mainly affect the crankcase interior without providing a clear path into the exhaust. • Ask: Under which condition would oil be most likely to seep or be drawn into the exhaust passage around a moving engine part?