🔍 Key Concepts

• How a diesel engine air starting system works during normal operation • What happens if an air starting valve does not fully close after starting • Effects of hot, high‑pressure air leaking into or out of a cylinder or starting air manifold

💭 Think About

• Once the engine is running normally, what should each air starting valve be doing? Open or fully closed? • If a starting air valve leaks on a running engine, where will the heat be generated: inside the valve, in the manifold, or in the line to that cylinder? What physical signs could that create? • Which option describes a local effect at a specific cylinder, rather than a general system condition?

✅ Before You Answer

• Identify which options describe system‑wide symptoms versus symptoms at one cylinder’s valve/pipe • Consider which symptom is directly caused by hot gas flowing where it should not be once the engine is running • Eliminate any choices that would more likely be caused by a failed compressor or major system loss, not just one leaking starting valve