Radiator Hose Fitting 1.5in Hose to #16 ORB

The Radiator Hose Fitting 1.5in Hose to #16 ORB from Holley is a precision adapter engineered for custom cooling system builds and high-performance engine modifications. This fitting bridges 1.5-inch hose diameters to industry-standard #16 ORB (O-Ring Boss) port connections, making it essential for builders upgrading to aftermarket radiators, water pumps, or remote oil coolers. Whether you're fabricating a fuel system upgrade or reconfiguring coolant lines on a naturally aspirated or turbocharged engine swap, this compact adapter eliminates the need for custom hose bends and reduces leak points.

Machined from durable materials with a compact 3.25 x 1.7 x 4-inch footprint and minimal 0.21 lbs weight, the Holley FB401 fitting maintains structural integrity under sustained pressure and thermal cycling. The #16 ORB port design provides a reliable sealing surface that accommodates standard O-ring gaskets, preventing weeping at connection points—critical when working with tight engine compartments where traditional hose clamps alone are insufficient. The 1.5-inch hose bore diameter accommodates modern silicone radiator hoses and braided stainless lines commonly used in street rods, race builds, and LS-swap applications.

Mechanics and enthusiasts favor this adapter when custom-plumbing cooling systems on engine conversions, particularly in vehicles with tight underhood spaces where stock hose routing is no longer feasible. Installation pairs easily with Holley's comprehensive cooling and fuel system product line, and the fitting threads directly into ORB-equipped radiator tanks, water pump ports, thermostat housings, and remote-mounted heat exchanger cores. Ensure proper O-ring sizing and anti-seize application on threads to achieve watertight seals under operating pressure; this fitting is compatible with both mechanical and electric cooling fan setups across carbureted and fuel-injected platforms.