Torque Solution TS-SU-679BK Billet Coolant Expansion Tank 02-22 WRX STI FXT BK

Vehicle Fitment

• 2002-2007 Subaru Impreza WRX (EJ205/EJ255)
• 2004-2022 Subaru WRX STI (EJ257)
• 2004-2008 Subaru Forester XT (EJ255)
• 2004-2006 Subaru Baja XT (EJ255)
• 2005-2006 Saab 9-2X Aero (EJ205)

Fitment Notes

• Mounts in the factory expansion tank location using the OEM bracket mounting points - no drilling or relocation required
• Compatible with the OEM coolant expansion tank cap - the factory cap transfers directly to this tank; a new cap is not needed
• Minor hose trimming may be required for proper installation depending on vehicle and existing hose condition
• Tank position is identical to OEM, preserving the ability to properly burp the cooling system using standard procedure
• This listing is for the Black anodized version (TS-SU-679BK) - also available in Silver (TS-SU-679S)
• A separate billet aluminum pedestal accessory is available as TS-SU-679-P for owners who want to raise the tank for improved visibility or cooling system aesthetics

Features

• CNC-machined 6061-T6 billet aluminum construction - replaces the OEM black plastic expansion tank, which is prone to cracking, stress fracturing, and coolant leaks as it ages and undergoes repeated heat cycling on EJ-series engines
• Black anodized finish with Torque Solution logo - corrosion-resistant and visually distinctive in the EJ engine bay
• Mounts in the stock OEM location - no bracket fabrication, no hose rerouting, and no changes to the coolant system's burp point
• Works directly with the OEM expansion tank cap - the factory cap threads onto this tank identically to the stock unit
• Eliminates the most common failure mode of the OEM plastic tank: stress cracking at the hose barb connections and at the seam lines, which accelerates dramatically on high-mileage or high-heat EJ builds
• Billet aluminum does not degrade, discolor, or become brittle from sustained coolant exposure and heat cycling - providing a functionally indefinite service life compared to the OEM plastic unit
• Stainless steel mounting hardware included - corrosion-resistant and correctly torqued for aluminum-to-chassis installation
• Limited Lifetime Warranty

Specifications

• Part Number: TS-SU-679BK
• Brand: Torque Solution
• Product Type: Billet Aluminum Coolant Expansion Tank
• Material: CNC 6061-T6 Billet Aluminum
• Finish: Black Anodized with Torque Solution Logo
• Cap: OEM Expansion Tank Cap Compatible (cap not included)
• Mount Location: OEM Stock Position
• Application: 2002-2007 Subaru WRX / 2004-2022 WRX STI / 2004-2008 Forester XT / 2004-2006 Baja XT / 2005-2006 Saab 9-2X Aero
• Warranty: Limited Lifetime

Included Components

• 1x CNC Billet Aluminum Coolant Expansion Tank (Black Anodized, assembled)
• 2x M8x14 Stainless Steel Button Head Bolt

Product Description

The Torque Solution TS-SU-679BK is a CNC-machined 6061-T6 billet aluminum coolant expansion tank engineered as a direct OEM replacement for the 2002-2007 Subaru Impreza WRX, 2004-2022 WRX STI, 2004-2008 Forester XT, 2004-2006 Baja XT, and 2005-2006 Saab 9-2X Aero. The OEM plastic expansion tank on these EJ-platform vehicles is a time-sensitive failure item: repeated heat cycling from the EJ-series cooling system gradually embrittles the plastic, and by the time most vehicles reach high mileage, the tank exhibits stress cracks at its hose barb connections, hairline fractures along its seam lines, and discoloration from prolonged coolant contact. On high-boost or track-used EJ builds, the thermal demands accelerate this degradation considerably. A cracked expansion tank leads to gradual coolant loss, elevated coolant temperatures, and in worst cases, a complete cooling system bleed that can result in overheating.

The TS-SU-679BK eliminates this failure mode entirely. CNC-machined 6061-T6 billet aluminum does not crack, craze, stress-fracture, or degrade from sustained heat cycling and coolant exposure - its service life in this application is functionally unlimited. The tank is designed to mount directly in the OEM factory location using the stock bracket mounting points and the two included stainless steel bolts, requiring no fabrication or bracket modification. It accepts the factory OEM expansion tank cap directly, and because it occupies the same position as the stock unit, the normal coolant system burping procedure works identically. Minor hose trimming may be required depending on the vehicle's existing hose condition.

This is the Black anodized version (TS-SU-679BK); a Silver version is also available as TS-SU-679S, and a separate billet aluminum pedestal accessory (TS-SU-679-P) is offered for owners who want to elevate the tank position. Backed by Torque Solution's Limited Lifetime Warranty.