Radium Engineering Coolant Expansion Tank- Universal

The Radium Engineering Universal Coolant Expansion Tank is designed for custom cooling systems that need a high-mounted fill and bleed point, including vehicles with rear-mounted radiators, V-mount radiator setups, engine swaps, and other non-standard cooling layouts. Unlike an overflow reservoir, this tank becomes part of the pressurized cooling system, allowing the radiator to remain completely filled with coolant while providing space for thermal expansion.

The 750mL tank is CNC machined from 6061 billet aluminum and uses a two-piece construction with internal crossover passages. An internal swirl chamber directs incoming hot coolant tangentially through the tank to help separate trapped air from the coolant before it returns to the engine, improving system bleeding and reducing aeration.

For flexible custom plumbing, the tank has a 6AN ORB inlet and two 10AN ORB bottom ports. Radium includes 6AN adapters, 90-degree Push-Lok hose ends, a sight tube, mounting bracket, pressure-bleed barb, and installation hardware. The billet cap receiver accepts a standard 32mm Type-A pressure cap, which is sold separately.