🔍 Key Concepts

• Fuel ash constituents and how sodium in fuel affects engine components at high temperature • Where corrosive attack is most likely: hot exhaust valves vs relatively cooler injection equipment • Difference between corrosion, gumming, and deposits in diesel engine systems

💭 Think About

• Which engine parts see the hottest combustion gases where sodium compounds would be carried and react? • Do sodium-related problems usually show up more on the exhaust side or on the fuel supply side of a diesel engine? Why? • Which option best matches the type of damage sodium salts plus high temperature are known to cause: mechanical wear, sticky residues, or chemical attack?

✅ Before You Answer

• Identify which components are exposed directly to hot combustion products rather than liquid fuel • Consider whether sodium compounds are more likely to form hard, corrosive deposits or soft, gummy residues • Check which choice describes a failure mode commonly associated with high-temperature salt corrosion in diesel engines