Radium Engineering Coolant Tank – Lotus Elise/Exige 2ZZ-GE, Firewall Mount

This Radium Engineering coolant header tank is designed for custom Lotus applications where the OEM tank is no longer ideal—such as engine swaps, turbo kits, or V-mount radiators. It features a high-mounted design to ensure proper system bleeding and coolant circulation.

Vehicle/Application Compatibility:

• Universal fitment for custom Lotus builds (e.g., turbocharged or engine-swapped S2 Elise/Exige)

• Ideal when the OEM expansion tank must be relocated

• Mounts cleanly to firewall or custom bracket locations

Overview:
Constructed from CNC machined 6061 aluminum, the Radium header tank features a 2-piece body bolted together for a precision seal. A CNC billet cap receiver accepts all standard 32mm “Type-A” pressure caps (not included). The tank incorporates an internal swirl feature designed to deaerate the system by accelerating coolant tangentially through a vortex chamber—reducing trapped air and promoting optimal cooling.

This setup is essential for low-mounted radiators, common in custom cooling configurations, where air naturally accumulates at the highest point in the system. By using this header tank as the system’s highest elevation, trapped air can be effectively purged.

Port Configuration:

• 2x Lower Ports: 10AN ORB

• 1x Side Port: 6AN ORB

• All ports come pre-installed with -6AN male adapter fittings

• Pressure bleed nipple and sight tube ports included

Key Features:

• CNC machined billet aluminum construction

• Black anodized for corrosion protection

• Integrated swirl pot for improved air separation

• Supports standard 32mm “Type-A” radiator pressure caps

• Multiple port options with included ORB to AN fittings

• Ideal for remote-mount coolant header setups