COBB Coolant Overflow Tank – 2008-2014 Subaru WRX / STI

Cobb Coolant Overflow Tank — 2008-2014 Subaru WRX / STI

The Cobb Aluminum Coolant Overflow Tank for the 2008-2014 Subaru WRX replaces the factory plastic coolant reservoir with a billet aluminum unit. Aluminum construction resists heat deformation and provides a premium visual finish at the factory mounting location.

DETAILS

• Platform: 2008-2014 Subaru WRX
• Billet aluminum construction — heat resistant, no deformation or discoloration
• Replaces factory plastic overflow bottle at factory location
• Factory mounting points — no relocation required
• Premium engine bay visual upgrade
• Factory overflow cap compatible

Billet Aluminum Construction vs Factory Plastic Overflow Bottle

The factory coolant overflow tank on most EJ and FA-series Subaru applications is a translucent plastic bottle positioned in the engine bay for simple function — it collects overflow coolant from the radiator cap and allows it to be drawn back when the system cools. On turbocharged builds where the engine bay is more densely packed with upgraded components, the factory overflow tank position and appearance can become a visual and functional issue. The Cobb aluminum coolant overflow tank replaces the factory plastic unit with a billet aluminum unit that resists heat deformation, provides a more consistent seal over time, and presents a premium visual finish in the engine bay.

Factory Location Installation and Heat Resistance

The Cobb overflow tank installs at the factory location using factory mounting points — no relocation or plumbing modification is required. The aluminum construction is more resistant to the sustained elevated temperatures that turbocharged engine bays experience compared to the factory plastic bottle, which can discolor, deform, and develop small seeps over time. The filler cap uses the factory overflow cap specification for correct pressure venting behavior.

What’s in the Box

• Cobb aluminum coolant overflow tank
• Mounting hardware

Why Choose Cobb Tuning

Cobb Tuning has been developing performance software and hardware for turbocharged enthusiast vehicles since 1999. Founded in Austin, Texas, Cobb built its reputation on the Accessport and expanded into a full catalog of hardware engineered to complement it. Every OTS map is developed in-house on real vehicles, and every hardware product is validated as part of a complete system — not sourced and sold in isolation. That integrated approach is why Cobb produces consistent, reliable results across the builds we see every day.

The RallySport Take

The Cobb aluminum coolant overflow tank for the 2008-2014 Subaru WRX is the engine bay detail upgrade that replaces a functional but visually dated plastic bottle with an aluminum unit that ages better and looks better. For builds with comprehensive engine dress work, the overflow tank is one of the most visible components in the Subaru engine bay.

Fitment

Year	Make	Model	Notes
2008-2014	Subaru	WRX	EJ255
2008-2021	Subaru	WRX STI	EJ257