12AN Flare Cap Nut 2 Piece Black

The 12AN Flare Cap Nut 2 Piece Black from REDHORSE PERFORMANCE is an essential hose end component for high-performance fuel, oil, and coolant systems in custom-built vehicles and engine modifications. Designed for mechanics and enthusiasts who demand reliable, leak-free connections in demanding automotive applications, this cap nut secures AN-spec hose fittings with precision engineering. Whether you're plumbing a fuel injection system, upgrading a turbo oil line, or assembling a custom cooling circuit, the 12AN flare cap nut provides the critical seal that keeps your system pressurized and safe under high-flow conditions.

This two-piece design incorporates a flared female seat that mates with a 37-degree AN hose end fitting, creating a metal-to-metal seal that resists vibration and thermal cycling better than single-piece alternatives. The black anodized finish not only provides corrosion resistance in underhood environments but also aids in identifying hose circuits at a glance during diagnostic work. The 12AN specification indicates a nominal hose ID of 3/4 inch, making this nut compatible with high-volume applications such as turbocharger feed and return lines, transmission cooler circuits, or fuel rails on carbureted and fuel-injected engines. The lightweight design—only 0.12 lbs—minimizes assembly weight while maintaining structural integrity under pressure differentials and vibration loads typical of performance driving.

This cap nut is ideal for fabricators and experienced DIY builders who are assembling custom fuel systems, upgrading coolant loops, or integrating auxiliary oil circuits on modified engines. Installation requires only a wrench or socket—no special tools needed—and the flare connection ensures a seal the moment you hand-tighten it. REDHORSE PERFORMANCE's reputation for precision manufacturing makes this component a trusted choice in competition fuel systems, street performance builds, and race engine applications where reliability cannot be compromised. Verify your hose end fittings match the 37-degree flare standard and 12AN sizing before assembly to guarantee a leak-free connection.