2.75 Pro Filler Cap & Bung - Weld-In

The 2.75 Pro Filler Cap & Bung - Weld-In from MEZIERE is a professional-grade coolant system component designed for custom cooling applications in performance vehicles and racing engines. This weld-in bung assembly provides a secure, permanent mounting solution for radiator caps and overflow management, making it essential for builders who demand reliability under extreme thermal conditions. The kit combines a durable aluminum bung with a threaded aluminum cap in natural finish, offering both functionality and a clean aesthetic in engine bays.

The 2.75-inch opening diameter accommodates standard Pro-style cooling caps, while the weld-in construction ensures permanent, leak-free integration into custom radiator tanks and overflow reservoirs. Aluminum construction throughout provides excellent corrosion resistance and thermal stability, critical factors in high-performance cooling systems where temperature fluctuations and pressure cycling are constant. The threaded cap design allows quick access for coolant level checks and system maintenance without compromising structural integrity or requiring secondary clamps or fasteners.

Engine builders, fabricators, and performance shops benefit most from this professional-grade filler cap kit when constructing custom cooling systems, prototype engines, or restoration projects requiring precision coolant management. Installation requires welding equipment and metallurgical expertise; the bung is designed for TIG or MIG welding into aluminum or steel tanks. This component is ideal for oval track racing, drag racing, street rod builds, and any application where OEM radiator tanks have been replaced or modified for enhanced cooling capacity or custom routing.