RADIUMAUTO Coolant Expansion Tank Kit, Elise/Exige, OEM position

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This kit is compatible with all S2 Elise and Exige models that use the Toyota 2ZZ-GE engine (N/A or turbocharged).

The Radium Coolant Expansion Swirl Tank features three fittings that use -6AN male adapters (non-tapered pipe threads) for a positive seal. The main tank is a 2-piece design machined from billet aluminum.

The two halves bolt together with a CNC machined aluminum cap receiver that fits any standard 32mm Type "A" pressure cap.

Radium Engineering's tank also features a vortex facility, as shown here. The pressurized coolant is directed tangentially into the inlet of the vortex chamber and is accelerated to a high rate of rotation. This is an old hot rod trick to help bleed the system.

The S2 Lotus Elise, Lotus Exige and Lotus 2-Eleven come standard with a Denso coolant expansion tank. This is the same plastic tank found in Toyota 2ZZ-GE equipped vehicles. For the installation, Lotus has developed a complex bracket that includes a bracket for the hot-soak electric water pump. Cases have been reported of the Denso tank failing and owners have found that new replacements are quite expensive. Radium simplified the Lotus construction with two separate brackets and further improved it with a robust aluminum tank and adapting the factory hoses to -6AN fittings.

The image below shows the Lotus plant (left) and the Radium plant (right).

The bracket uses all factory-installed threaded holes. Because of this there is no need to drill or modify anything as there is in screws. Installation is a fairly simple process that can be performed by an average mechanic. Everything is accessible with the tailgate intact. Aluminum Push-Lok hose ends are included to convert factory coolant hoses to -6AN.

Contains :
- Aluminum coolant tank, black anodized
-Nickel plated sight tube fittings
-Aluminum 6AN Male Adapter Fittings Black Anodized
-Aluminum 6AN hose ends Black anodized
Laser cut aluminum tank mount, powder coated black
Laser Cut Aluminum Hot Soak Water Pump Bracket Anodized
Rubber insulation grommets for the coolant tank
Hot Soak Water Pump Pillow Clip
-Mounting material

Options :
Radium Engineering's optional pressure caps (sold separately) allow the user to select a pressure range that was not possible with the Denso tank. The purpose of a high-pressure cap is to increase the boiling point in the cooling system, thereby improving cooling efficiency. Each lid is machined from stainless steel with a race-proven high-pressure valve. This is something to consider when driving the vehicle in extreme conditions.

Note : The OEM Lotus pressure cap is 1.1Bar.