GM Radiator 21 x 30.75 Dual Pass

The AFCO Racing Products GM Radiator 21 x 30.75 Dual Pass (part number 80120N) is a purpose-built aluminum cooling solution engineered for high-performance marine engine applications where reliable heat rejection directly impacts on-water reliability and engine longevity. Constructed from aluminum with passenger-side inlet and outlet configuration, this dual-pass radiator delivers consistent coolant flow management across demanding offshore and freshwater boating conditions where engine temperatures can spike during extended trolling, high-speed runs, or continuous operation in tropical climates.

The 21-inch height by 30.75-inch width footprint accommodates standard engine bay configurations while the 3-inch depth maintains compatibility with space-constrained installations common in center console and sportfisher builds. Dual-pass core design maximizes coolant contact time within the radiator matrix, improving heat transfer efficiency compared to single-pass designs. At 22.5 pounds, the aluminum construction provides weight efficiency without sacrificing structural rigidity—a critical consideration for performance vessels where every pound affects fuel economy and handling. The natural aluminum finish resists corrosion in salt environments when properly maintained, though marine operators typically apply protective coatings to extend service life in aggressive saltwater exposure.

This radiator serves weekend fishermen with modest cruising vessels and serious offshore anglers running twin or triple-engine configurations where precision cooling prevents mid-trip shutdowns. Replacement radiators are essential when original equipment shows signs of corrosion, leakage, or reduced cooling capacity—conditions that develop gradually in saltwater environments but can leave you stranded miles from shore. The specific inlet/outlet positioning requires verification against your engine's cooling system plumbing before installation to ensure proper flow direction and hose compatibility.