The McCormick 6507098M91 is a genuine OEM radiator cap designed for optimal cooling system pressure regulation. This cap maintains a pressure of 0.9 bar (13 PSI) to ensure efficient engine cooling and prevent coolant loss. It is a direct fit for various McCormick tractor series, including C, CX, MC, MTX, XTX, and ZTX models. Also compatible with select Massey Ferguson 5400, 6400, 7400, and 8400 series tractors, ensuring broad application across agricultural machinery.