Coolant Hose Fitting 1in NPT to 1-1/4 Slip

The Aeromotive Coolant Hose Fitting 1in NPT to 1-1/4 Slip (Part Number 15771) is a precision adapter designed to facilitate reliable connections between threaded NPT ports and barbed hose fittings in high-flow cooling systems. Constructed from aluminum with black anodized finish, this straight adapter fitting converts a 1-inch NPT male thread to a 1-1/4-inch hose barb, enabling seamless integration of coolant lines in performance engines, racing applications, and heavy-duty cooling circuits where secure, leak-free connections are essential.

The 1-1/4-inch slip connection accommodates standard coolant hose sizes commonly found in engine bays and custom cooling systems, while the NPT male thread provides a secure, industry-standard port interface. Aluminum construction delivers a lightweight solution without sacrificing durability, and the black anodized finish protects against corrosion in the presence of coolant chemicals and engine compartment moisture. The straight configuration eliminates unnecessary bulk and facilitates direct routing in confined spaces around engine blocks and radiator inlets.

This fitting is engineered for use in custom cooling system builds, engine swaps, and performance modifications where OEM coolant ports may not align with aftermarket radiators or water pump configurations. Aeromotive specializes in fuel system and cooling system components for high-performance automotive applications, making this adapter a trusted choice for builders seeking reliable thread-to-hose transitions. The NPT to slip conversion is particularly valuable in applications requiring quick disconnection, flexible hose routing, or connection to non-standard cooling components where direct NPT female ports are unavailable.

When specifying coolant hose fittings, confirming both thread type (NPT male) and hose barb size (1-1/4 inches) is critical to prevent leaks and ensure proper system flow. This single-unit adapter is suitable for engines operating in high-temperature, high-pressure cooling environments, provided that hose clamps rated for the system's operating pressure are used to secure the hose to the barbed end.