Radium Engineering Coolant Tank Kit | 2015-2017 Ford Mustang (20-0286)

The S550's plastic coolant tank is the one part of the engine bay guaranteed to yellow, crack, and quit.

Ford's factory reservoir does its job until heat cycles turn it brittle. The Radium Engineering Coolant Tank Kit for the 2015+ Mustang replaces the plastic tank at the front of the engine bay with a cast aluminum, two-piece welded swirl tank topped by a CNC billet cap receiver that mates to any standard 32mm import-style pressure cap. Three ports run 6AN ORB (9/16"-18) adapters for a positive O-ring seal instead of tapered pipe threads, and the internal swirl architecture deaerates coolant as it circulates. One of the few upgrades that improves the cooling system and the view under the hood equally.

What You'll Feel

• A coolant tank that will never crack, cloud, or weep like the aging factory plastic
• Deaerated coolant circulating, with the swirl design separating entrained air
• Positive O-ring sealed connections on all three ports, no pipe-thread leaks
• A pressure cap upgrade path with any standard 32mm import-style cap, including Radium's 1.1/1.3/1.5 Bar caps
• An engine bay centerpiece where a plastic jug used to sit

Features

• 2-piece cast aluminum main tank, welded, with CNC billet aluminum cap receiver
• Accepts any standard 32mm import-style pressure cap (cap sold separately)
• Three ports using 6AN to 9/16"-18 O-ring adapters for a positive seal, not tapered pipe threads
• Internal swirl design aids in deaerating the cooling system
• Direct replacement for the plastic coolant tank at the front of the engine bay
• Stainless steel hardware

The Details

The swirl tank concept borrows from Radium's expansion tank playbook: coolant entering the tank is set into rotation, and the spin separates air bubbles from the liquid before it returns to circulation, protecting the water pump from aeration and keeping heat transfer surfaces wetted with coolant instead of foam. The ORB port architecture matters for longevity, since O-ring boss connections seal positively and re-seal after service, where NPT joints loosen a little every time they are touched. Cap selection is the tuning knob: Radium's optional stainless 1.1, 1.3, and 1.5 Bar Type-A caps raise the system's boiling point for track duty, which is worth considering on a car that sees sustained load. Installation replaces the factory tank in its original location with the included hardware.

Kit Includes

• 1x Cast aluminum coolant swirl tank with CNC billet cap receiver
• 3x 6AN ORB adapter fittings
• Stainless steel hardware
• Pressure cap NOT included; accepts standard 32mm import-style caps

Applications

• 2015-2017 Ford Mustang GT, EcoBoost, V6, and Shelby GT350 (S550, per Radium's kit coverage for the platform)
• Pairs with Radium 1.1/1.3/1.5 Bar pressure caps, sold separately