Radiator Aluminum Filler Neck

The Radiator Aluminum Filler Neck from Northern Radiator is a weld-on component designed for builders and mechanics who demand reliability in custom cooling systems. This universal filler neck accommodates standard radiator caps and serves as the intake point for coolant in both street and performance applications. Whether you're fabricating a custom chassis, restoring a classic, or upgrading a modern build, this aluminum neck provides a clean, functional connection between your coolant reservoir and radiator core.

Constructed from lightweight aluminum, the Radiator Aluminum Filler Neck resists corrosion and integrates seamlessly into custom welded radiator assemblies. The weld-on design allows full control over positioning and orientation within your cooling layout, critical for tight engine bays or unconventional plumbing routes. Northern Radiator's engineering ensures the cap-style neck accepts common aftermarket and OEM caps without modification, maintaining system integrity under pressure while the compact 1.25-inch neck diameter suits most radiator inlet configurations used in hot rod and performance engine swaps.

This component is ideal for fabricators, race teams, and restoration shops building custom cooling systems from bare cores or remanufactured radiators. Its universal fit eliminates fitment guesswork across different vehicle platforms and engine swaps, making it a go-to solution for mid-engine conversions, transplants, and purpose-built race cars. The lightweight aluminum construction reduces unsprung mass—a benefit felt in suspension tuning—while the durable material withstands thermal cycling and vibration inherent to high-performance use. Installation requires basic TIG or MIG welding skills and positioning the neck at the highest point of your radiator tank to ensure proper coolant fill and air purge.