Radium Coolant Expansion Swirl Tank - Lotus Elise / Exige (2006-2011, 2ZZ-GE)

Suits:

• 2006-2011 Lotus Elise — 2ZZ-GE
• 2006-2011 Lotus Exige — 2ZZ-GE

The Radium Engineering Coolant Expansion Swirl Tank is a remote-mounted header tank designed for custom Lotus applications including engine swaps and turbocharger kits where the OEM expansion tank is no longer in an ideal location. Essential for applications using a low-mounted radiator such as a V-mount, where proper air bleeding requires a correctly positioned header tank.

Construction

Two-piece design CNC-machined from 6061 billet aluminium. The two halves are bolted together along with a CNC billet aluminium cap receiver that mates to any standard 32mm Type-A style pressure cap.

Internal Swirl / Vortex Deaeration

Hot pressurised coolant from the cylinder head enters the vortex chamber tangentially and is accelerated to a high rate of rotation. This proven technique aids in deaerating the coolant system — removing entrained air bubbles that can cause hot spots and reduce cooling efficiency.

Ports

• Lower ports (x2): 10AN ORB threads with 6AN male adapter fittings
• Side port (x1): 6AN ORB threads with 6AN male adapter fitting
• All fittings use AN ORB (not tapered pipe threads) for a positive, leak-free seal

Part Number:

• 20-0270-02 — Radium Coolant Expansion Swirl Tank (Lotus Elise / Exige 2006-2011, 2ZZ-GE)

Why Radium Engineering?

• ✅ Manufactured in the USA to motorsport-grade tolerances
• ✅ CNC-machined billet aluminium components built for performance and longevity
• ✅ Trusted by high-power build tuners and race teams worldwide
• ✅ Bolt-on fitment — no cutting, drilling, or fabrication required
• ✅ Internal vortex deaeration — proven hot rod technique for superior coolant system performance