The Radium remote mounted coolant header tank is commonly required for custom Lotus applications such as engine swaps, turbocharger kits, etc. where the OEM expansion tank is no longer in an ideal location.

The main tank is a 2-piece design constructed of CNC 6061 billet aluminum, as shown below. The two halves are bolted together along with a CNC billet aluminum cap receiver which mates to any standard 32mm "Type-A" style pressure cap. Coolant header tanks are necessary for applications that utilize a low mounted radiator, such as a V-Mount, for proper air bleeding.

The Radium Engineering tank also has an internal swirl feature. 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 an old hot rod trick to help aid in deaerating the system.

The Radium Coolant Expansion Swirl Tank features three ports that include -6AN male adapter fittings (not tapered pipe threads) for a positive seal. The lower ports are machined with 10AN ORB threads. The side port is machined with 6AN ORB threads.