This injector washer seals the interface between the injector body and the cylinder head in the host tractor's engine. It prevents combustion gas leakage and maintains the correct compression pressure within the cylinder. A worn or missing washer allows blow-by, which reduces engine power and can carbon-foul the injector seat. The washer is an original component, meaning its thickness and material specification match the factory design so that the injector clamping load and protrusion remain within tolerance. On reinstallation, ensure the sealing surfaces are clean and the injector hold-down bolts are torqued to the specified value.