Radiator Caps & Filler Necks

Ace Race Parts offers a comprehensive selection of 6061 aluminum radiator filler necks in two common sizes—Small and Large—along with high-pressure radiator caps from Koyo and Mishimoto. Each radiator filler neck is precision CNC machined from billet 6061 aluminum and features a two-piece threaded design, ensuring a secure and reliable fit. Our radiator filler necks are designed to accommodate both import and domestic-sized radiators, as well as custom radiator setups.

In addition to our radiator filler necks, Ace Race Parts also offers precision CNC machined Tank Weld Bungs, crafted from solid 6061 aluminum billet. These Tank Filler Necks, or Tank Weld Bungs, come with a thread-on cap featuring an O-ring for a secure seal. Available in five different sizes, our Tank Weld Bungs are versatile components that can be used to fabricate a wide variety of tanks, making them ideal for custom builds and modifications.

With Ace Race Parts, you can trust in the quality and precision of our aluminum components, whether you're working on a radiator or fabricating a custom tank.