Radiator Inlet Fitting 1-5/8in x -16AN

The Radiator Inlet Fitting 1-5/8in x -16AN from Northern Radiator is a precision adapter designed for custom cooling system installations and high-performance engine builds. This straight-flow fitting bridges the gap between 16 AN male and 20 AN O-ring ports, making it essential for builders who need to route coolant lines through non-standard chassis layouts or upgrade existing radiator plumbing. Whether you're fabricating a custom cooling loop, converting from stock hose to AN hardline, or connecting aftermarket radiators to modern engine bays, this fitting delivers the reliable port compatibility that professional mechanics and serious enthusiasts demand.

Machined from aluminum and finished in clear anodize, the Radiator Inlet Fitting 1-5/8in x -16AN resists corrosion while maintaining a lightweight profile critical for performance builds. The straight design eliminates flow turbulence that angled fittings introduce, preserving coolant velocity and reducing pressure drop across the connection point. The 1-5/8-inch body length provides optimal spacing for tight engine compartments, while the 16 AN male thread (standard -16 JIC 37-degree flare) pairs directly with -20 AN O-ring female ports found on modern aluminum radiators, water pumps, and billet manifolds. Clear anodize coating ensures long-term durability against ethylene glycol, propylene glycol, and water-methanol mixtures used in street and race cooling systems.

This fitting serves LS engine conversions, supercharged and turbocharged installations, custom hot rods, and race car builds where stock radiator inlet ports are either relocated or replaced entirely. Mechanics upgrading from rubber hose to rigid AN lines benefit from the secure, leak-free O-ring seal that eliminates hose creep and simplifies troubleshooting. Use with -16 AN male hose ends, braided stainless lines, or hard tubing to complete custom cooling circuits. The compact 0.2-pound weight makes it suitable for weight-sensitive racing applications, while the machined aluminum construction resists vibration-induced loosening common in high-RPM environments.