The John Deere AP23771 is a genuine OEM pressure cap designed for a wide range of John Deere agricultural and construction equipment. This cap maintains a precise 7 PSI (0.48 bar) pressure within the cooling system, ensuring optimal engine performance and preventing coolant loss. It supersedes part numbers AT20779, AT19478, AT18478, and AT17478, making it a reliable replacement for older models. Engineered for durability and exact fitment, this pressure cap is crucial for the efficient operation of your John Deere machinery.