-20an Female Aluminum O-Ring Weld-In Bung

The MEZIERE -20AN Female Aluminum O-Ring Weld-In Bung is a precision port fitting designed for custom cooling system fabrication and high-performance engine builds. This component serves as a mounting point for auxiliary accessories—thermostatic switches, temperature sensors, or auxiliary coolant lines—on aluminum radiators, water blocks, and custom manifolds. Whether you're building a street performance engine, race car cooling circuit, or modifying an existing system, this weld-in bung provides a clean, permanent solution where drilling and tapping may compromise structural integrity or coolant flow.

Manufactured from lightweight aluminum alloy, the -20AN Female Aluminum O-Ring Weld-In Bung features an integral O-ring groove that creates a reliable, leak-free seal when paired with matching -20AN male fittings and sealing rings. The weld-in design eliminates the need for mechanical clamping or complex adapter stacks; the bung is TIG-welded directly into aluminum castings, sheet, or fabricated tanks, ensuring structural permanence and eliminating vibration-induced loosening common with threaded connections. The female port accepts standard -20AN hose fittings and adapters, maintaining compatibility with industry-standard fuel system and coolant line components used throughout the performance automotive and motorsports sectors.

Engine builders, fabricators, and motorsports enthusiasts benefit most from this bung when designing closed-loop cooling systems, integrating thermostat housings, or routing remote oil cooler lines through aluminum radiators and custom water tanks. Its compact footprint and straightforward installation make it ideal for tight engine bays where space constraints rule out larger threaded ports or bulkhead fittings. Ensure your TIG welder is equipped for aluminum and verify that your cooling system design accounts for the bung's internal diameter to avoid flow restriction or sediment accumulation at high coolant velocities.