Water Pump Hose Adapter - 1-1/4 x 16an

The Water Pump Hose Adapter – 1-1/4 x 16AN is a critical fitting for builders and enthusiasts upgrading cooling systems on high-performance and custom vehicles. This adapter bridges the gap between oversized cooling passages and modern ANJ (AN Joint) hose standards, enabling seamless integration of aftermarket water pump housings, radiator modifications, and custom coolant loops. Whether you're performing a complete engine bay overhaul, installing a higher-flow pump, or transitioning legacy cooling systems to modern plumbing, this adapter delivers the reliability and precision fit that serious engine builders demand.

Engineered for durability and leak-free performance, the water pump hose adapter features a 1-1/4 inch port size mated to a 16AN (AN16) JIC flange connection, accommodating both metric and SAE cooling passages commonly found in LS swaps, turbo conversions, and engine transplants. The 16AN outlet allows direct attachment to industry-standard braided or rubber hose lines without additional reducers, maintaining optimal coolant flow rates and pressure consistency under sustained boost or high-RPM operation. Compact at 4.5 x 4.2 x 4.6 inches and weighing just 0.32 pounds, the adapter installs in confined engine bays while resisting vibration fatigue and thermal cycling that would compromise inferior alternatives.

This adapter is indispensable for fabricators working on LS-based powerplants, modern Ford modular swaps, or any platform requiring custom coolant routing between performance water pumps and modern hose standards. Compatibility depends on your pump outlet diameter—verify that your water pump features a 1-1/4 inch port before ordering. Installation is straightforward: thread or flange-mount the adapter to your pump housing, then connect your 16AN braided hose using standard AN fittings. Pair this adapter with quality coolant hose, proper clamps, and a thermostat bypass system for a cooling setup engineered to handle continuous track use or street duty without compromise.