This fuel pump gasket seals the interface between the fuel pump and the engine block, preventing air ingress and fuel leakage at the mounting flange. It sits between the pump housing and the block face, where it maintains a leak-free seal under the clamping load of the mounting bolts. A degraded gasket allows air to enter the fuel system, causing hard starting, erratic idle, or loss of prime. The gasket is formed to match the original seal groove geometry, so it compresses evenly without over-stressing the pump flange. On reinstall, clean both mating surfaces and tighten the mounting bolts to the specified torque.