Coolant expansion tanks are necessary for proper air bleeding in applications that utilize a rear mounted radiator or a low mounted radiator such as a V-Mount. However, expansion tanks are also valuable if integrated in a common radiator setup. To allow heat expansion, traditional coolant systems require air to be present in the top portion of the radiator during low temperatures. A coolant expansion tank permits the radiator to be 100% filled with coolant in all conditions.

This Radium Coolant Expansion Tank holds 822mL. It is a 2-piece design constructed of CNC billet 6061 aluminum. The two halves (shown below) are bolted together along with a CNC billet aluminum neck.

A pressure cap is not included. The CNC billet receiver is compatible with Type-A "radiator" caps, as shown HERE. The tank features two internal chambers. These chambers are NOT isolated from each other. There are cross-over passages at the top and bottom. 

This product is not a coolant overflow tank. Instead, it is designed to be a part of the pressurized coolant system.

The Radium Engineering coolant expansion tank also has an internal swirl feature, as shown. Hot pressurized coolant from the cylinder head is sent into the vortex chamber's inlet tangentially and accelerated to a high rate of rotation. This is to prevent aeration in the system.

PRESSURE CAPS

The optional Radium Engineering pressure caps (sold separately) allow the user to select a range of pressure. The purpose of a high pressure cap is to increase the boiling point in the cooling system providing improved cooling efficiency. Each cap is manufactured from stainless steel with a race proven high pressure valve. This is something to consider when tracking the vehicle in extreme conditions. For more information, go HERE.

Radium Pressure Cap - 1.1 Bar (110 kPA, 15.6 psi)
Radium Pressure Cap - 1.3 Bar (130 kPA, 18.9 psi)
Radium Pressure Cap - 1.5 Bar (150 kPA, 21.8 psi)

The coolant tank has the following ports

• 6AN ORB (9/16"-18) port at the top/side. This is the inlet for incoming hot water.
• 10AN ORB (7/8"-14) bottom port directly under the inlet. This is the outlet for outgoing water upstream of the water pump
• 10AN ORB (7/8"-14) bottom port under the cap. This is used for an air bleed port
• Barbed cap fitting. This is the overflow/purge port

• Billet Aluminum Coolant Tank
• Anodized Aluminum Mounting Bracket
• 6AN Male Adapter Fittings (x3)
• 6AN 90 degree Push-Lok Hose Ends (x3)
• Nickel-Plated Fittings and Sight Tube
• Billet Aluminum 32mm Pressure Cap Receiver
• Aluminum Pressure Bleed 1/4" Barb
• Stainless Steel Hardware