This fuel injection o-ring seals the connection between the injector and the fuel line on the engine. It prevents fuel leakage and air ingress at the high-pressure joint. A degraded or hardened o-ring causes a loss of injection pressure, leading to hard starting, misfiring, or visible fuel seepage around the injector base. Manufactured by AGCO, this original part is formulated to withstand the fuel composition and temperature range of the host engine, matching the groove dimensions of the original injector body so no additional sealant or adapter is required. Replace the o-ring whenever the injector is removed; lubricate it with clean fuel oil before installation to prevent rolling or pinching.