Radium Coolant Expansion Tank KitBecause of continuous and intense heat cycling, plastic coolant tanks have a reputation of failing over time. Fortunately, the rugged 2 piece Radium Engineering replacement is CNC machined from aluminum and anodized for increased longevity. And because aluminum is a superior thermal conductor material, heat transfer is further improved. Additionally, the metal construction is robust enough to use in racing applications. This 2017+ Honda Civic Type R