🔍 Key Concepts

• Compatibility of gasket material with fuel oil at high pressure and temperature • Resistance to swelling, softening, or dissolving in petroleum products • Typical gasket materials used on diesel fuel injection and high‑pressure fuel systems

💭 Think About

• Think about which material will maintain a good seal without breaking down when exposed to hot diesel fuel at high pressure. • Ask yourself which materials on the list are more commonly used for pipes carrying very hot, pressurized liquids versus low‑pressure or cold services. • Consider what happens if the gasket material is slightly extruded or softened into the line on a high‑pressure system—would that be safe for fuel oil?

✅ Before You Answer

• Eliminate any material that is easily attacked or softened by oil or fuel. • Eliminate any material that is more suitable for insulation or low‑pressure services rather than tight metallic seals. • Focus on which material can form a metal‑to‑metal type seal and is commonly used in fuel injection or high‑pressure hydraulic lines.