Aluminum Fitting -8AN x 5/18-18 O-ring

The Aluminum Fitting -8AN x 5/8-18 O-ring from DERALE is a precision straight-port adapter designed for high-pressure hydraulic and fuel line systems in performance vehicles, racing applications, and custom builds. This fitting bridges two critical connection standards—the 8 AN (AN8) male port and the 5/8-18 male O-ring port—allowing seamless integration between incompatible line systems without leakage or pressure loss. Professional technicians and enthusiasts rely on this adapter when reconfiguring cooling systems, fuel delivery, or brake circuits that demand exact port matching.

Constructed from aerospace-grade aluminum, the Aluminum Fitting -8AN x 5/8-18 O-ring delivers lightweight durability without sacrificing strength or corrosion resistance. The straight-port design minimizes flow restriction and turbulence, critical for applications where pressure stability and thermal management matter. The integrated O-ring seal on the 5/8-18 side creates a metal-to-metal face-seal connection that accommodates system vibration and thermal cycling—typical stresses in engine bays and transmission cooler installations. Aluminum construction also resists anodic corrosion when properly installed, ensuring long service life in fuel and coolant environments.

This fitting suits custom cooling setups, aftermarket fuel rail upgrades, and engine swap projects where stock AN8 ports must connect to legacy 5/8-18 threaded bosses. Installation requires no special tools beyond standard wrenches; hand-tighten first, then apply controlled torque to avoid over-stressing the aluminum body. Verify that both ports are clean and free of debris before assembly, and confirm system pressure ratings match this fitting's load capacity to prevent failure. Weight and compact dimensions make it ideal for tight engine compartments where space is at a premium.