The Grizzly Air GA107 EGR Cooler provides your 5.9L Cummins (OE# 4089256NX) with proper function. Grizzly Air components are manufactured from high-quality components for a long life and factory-like performance. A failed EGR cooler can block coolant flow causing engine damage and overheating. Each Grizzly Component is designed as a bolt-on replacement.