IAG Coolant Expansion Tank Black – 2002-2007 Subaru WRX / STI

IAG Coolant Expansion Tank — Black — 2002-2007 Subaru WRX / STI

Billet Aluminum Coolant Expansion Tank for 02-07 WRX and STI
The IAG Coolant Expansion Tank for 2002-2007 WRX and STI replaces the OEM plastic coolant expansion (overflow) reservoir with a machined aluminum unit. The OEM plastic reservoir can crack with age, particularly in turbocharged applications where cooling system pressures are elevated. IAG’s aluminum tank provides improved durability and a cleaner engine bay appearance. Available in Black anodized finish.

DETAILS

• Color: Black anodized finish
• Machined aluminum construction
• Replaces OEM plastic coolant expansion reservoir
• More durable than OEM plastic in turbocharged applications
• Direct bolt-in replacement
• Fits: 2002-2007 WRX / STI

Why Replace the OEM Tank
The OEM plastic coolant overflow reservoir is prone to cracking with age, especially in the elevated heat and pressure environment of a turbocharged engine. A cracked reservoir causes coolant loss, which can lead to overheating. IAG’s aluminum tank eliminates this failure mode with a material that is unaffected by the pressures and temperatures in the cooling system.

Clean Engine Bay Appearance
The aluminum tank also improves the visual quality of the engine bay over a yellowed or cracked OEM plastic reservoir — a meaningful consideration for show-quality and detail-focused builds.

Direct Replacement
IAG’s coolant expansion tank installs in the same location as the OEM reservoir using existing mounting hardware. No modification is required.

Why Choose IAG Performance

IAG Performance has been building Subaru-specific engine and drivetrain components since 2001, and in that time they have become the standard by which serious Subaru builds are measured. Based in Westminster, Maryland, IAG designs, machines, and assembles their products in-house using Haas CNC equipment and their own engineering team. Their catalog spans everything from short blocks and long blocks rated to 1150 BHP all the way down to the fuel system, oiling, and drivetrain hardware that keeps modified Subarus running reliably for years. Every IAG product exists because a problem needed a better solution than what was available — and the engineering shows.

The RallySport Take

The IAG Black coolant expansion tank is a functional upgrade and a visual improvement over the OEM plastic reservoir. On any modified 02-07 WRX or STI, replacing the factory reservoir with aluminum is a practical preventative maintenance step.

Fitment