Chevrolet, GMC Radiator - Active Radiator Supply Company 5800-29, 1-800-Radiator 2403400, Serck FLA000858, Reach Cooling 42-10428

If you are sourcing a radiator for a 2003-2007 Chevrolet Kodiak or GMC Topkick, the Reach Cooling 42-10428 is the aftermarket direct replacement built to meet or exceed OE specifications. This aluminum-core, down-flow radiator cross-references Active Radiator Supply Company 5800-29, 1-800-Radiator 2403400, Serck FLA000858, NAPA NR4210428, Paccar Parts RAD42-10428TRP, and OSC HD9273, covering a wide range of fitment options across the C4500, C5500, C6500, and C7500 in both Kodiak and Topkick configurations. Engine coverage spans the 6.6L, 7.2L, 7.8L, and 8.1L options offered in these trucks from 2003 through 2007. Construction highlights include B-type tubes with central reinforcement for improved pressure tolerance, deep extrusion headers that resist vibration and thermal expansion at the tube-to-header joint, folded fin edges for better heat disbursement, and thermal expansion cuts that allow the core to breathe through normal heat cycles. Longer header tabs reduce the risk of tank-to-header leaks, and multi-fit attachments provide broad vehicle coverage without sacrificing proper fit. For mechanics and fleet buyers who need a proven, correctly fitting radiator for the Chevrolet Kodiak or GMC Topkick medium-duty platform, Reach Cooling 42-10428 delivers a dependable drop-in solution.