Radium Engineering Coolant Tank Kit – Lotus Elise/Exige 2ZZ-GE, OEM Location

This Radium Engineering swirl tank is a high-performance replacement for the factory Denso plastic expansion tank found on 2ZZ-GE equipped Lotus models. It’s compatible with both naturally aspirated and supercharged variants and features a robust, CNC-machined aluminum two-piece design for improved durability, function, and serviceability.

Vehicle Compatibility:

• Lotus S2 Elise (N/A Toyota 2ZZ-GE)

• Lotus S2 Elise (Supercharged Toyota 2ZZ-GE)

• Lotus S2 Exige (N/A Toyota 2ZZ-GE)

• Lotus S2 Exige (Supercharged Toyota 2ZZ-GE)

Overview:
The OEM Denso plastic coolant tank is known to crack over time and is expensive to replace. The Radium aluminum tank improves long-term reliability and integrates a swirl pot feature to help deaerate the cooling system. The design includes -6AN male ports for a secure, leak-free connection. The included brackets allow for factory-style mounting using existing threaded holes, with no permanent modifications required.

The swirl feature uses a tangentially fed inlet to promote vortex motion within the tank, aiding in bubble separation and helping maintain consistent coolant flow under high-performance conditions.

Key Features:

• CNC machined billet aluminum construction

• Integrated swirl pot for air separation

• 2-piece bolted design for serviceability

• Compatible with standard 32mm “Type-A” radiator caps

• Fully AN-adapted (-6AN) for leak-free sealing

• Mounts using factory threaded holes

• Retains OEM hot-soak water pump bracket