12AN Male to 16AN O-ring Port Adapter Black

The 12AN Male to 16AN O-ring Port Adapter Black from REDHORSE PERFORMANCE is a precision hydraulic fitting designed for custom fuel system builds, boost line plumbing, and fluid transfer applications where size adaptation is critical. This adapter bridges two common AN port standards—the 12AN male thread and 16AN o-ring boss port—allowing seamless integration of components that would otherwise be incompatible. Whether you're building a turbocharged fuel system, upgrading coolant circulation on a modified engine, or routing custom brake or transmission cooling lines, this compact fitting eliminates the need for undersized hose or restrictive workarounds.

Built from durable aluminum with black anodized finish for corrosion resistance and clean aesthetics, the adapter features an integrated o-ring seal at the 16AN port to ensure leak-free connections under pressure. The o-ring design eliminates the need for thread sealant tape and provides superior sealing performance compared to straight thread adapters, critical when working with boost systems, fuel injection, or engine coolant under elevated temperatures and PSI. The male 12AN thread on the inlet side accepts standard 12AN hose fittings or male-threaded components, while the 16AN o-ring port accommodates block ports or female-threaded cavities common in modern performance engines and aftermarket manifolds.

This adapter is essential for builders upgrading fuel system components, installing larger turbo intercooler piping, or adapting late-model engine ports to classic fuel line standards. Mechanics and fabricators working with LS, LT, and modern GM engines benefit greatly, as do Subaru, Mitsubishi, and Ford tuners where custom cooling or fuel pressure line routing is required. Installation requires no special tools—simply thread the 12AN male end into your hose fitting or component, then seat the o-ring port firmly into the 16AN female boss until hand-tight. Use this adapter where flow capacity, seal reliability, and compact design matter most.