🔍 Key Concepts

• Closed-loop diesel engine jacket water cooling system layout (pump, engine, headers, expansion tank) • Purpose of water treatment chemicals in jacket water (corrosion & scale control) • Where make‑up water is normally added and where flow/mixing are gentle

💭 Think About

• In a closed cooling system, where is the most convenient and safest point to add make‑up water or chemicals without shocking the engine with cold or concentrated fluid? • Which of these locations normally has lower pressure, easier physical access, and good circulation to mix chemicals throughout the system? • Which option, if used, would be least likely to introduce air into the pump or cause localized high chemical concentration on hot metal surfaces?

✅ Before You Answer

• Identify where the system is vented and open to atmosphere in a typical jacket water system. • Determine which point is normally used for filling and checking coolant level, not just for flow through the engine. • Eliminate any option that would risk cavitation at the pump or direct contact of strong, unmixed chemicals with hot engine surfaces.