Mishimoto MMRT-WRX-08E Aluminum Coolant Expansion Tank for 2008-2014 Subaru WRX

Vehicle Fitment

• 2008-2014 Subaru Impreza WRX (Base, Premium, Limited, 2.5L EJ255 Turbo, MT/AT)
• 2005-2009 Subaru Legacy GT (Base, Limited, 2.5L EJ255 Turbo, MT/AT)
• 2005-2009 Subaru Outback XT (Base, Limited, 2.5L EJ255 Turbo, MT/AT)
• 2009-2013 Subaru Forester XT (Base, Premium, Limited, Touring, 2.5L EJ255 Turbo, MT/AT)

Fitment Notes

• Does NOT fit the Subaru WRX STI - STI owners should use the MMRT-WRX-01E instead.
• May not fit with the stock air intake "S" hose - an aftermarket intake is recommended for best clearance.
• Compatible with both the stock Subaru radiator cap and the Mishimoto Performance Aluminum Radiator cap.
• Available in polished silver (MMRT-WRX-08E) and anodized black (MMRT-WRX-08EBK) - both use the same tank and fitment.
• The polished silver finish is designed to match the Mishimoto Performance Aluminum Radiator (MMRAD-STI-08).

Features

• TIG-welded all-aluminum construction eliminates the cracking and failure modes of the stock plastic expansion tank under repeated thermal cycling.
• 22% greater fluid capacity than the OEM plastic tank (566cc total) provides additional coolant reserve for high-heat and track use.
• CNC-machined barbed fittings are fully welded for leak-free connections at all coolant line attachment points.
• Polished silver finish matches the Mishimoto Performance Aluminum Radiator for a cohesive engine bay appearance.
• Compatible with both the stock Subaru radiator cap and the Mishimoto high-pressure radiator cap.
• Direct-fit design - no cutting, trimming, or fabrication required for installation.
• Backed by Mishimoto's Lifetime Warranty.

Specifications

• Material: TIG-Welded Aluminum
• Finish: Polished Silver
• Overall Height: 124 mm (4.88 in.)
• Overall Width: 100 mm (4.0 in.)
• Overall Length: 158.75 mm (6.25 in.)
• Fluid Capacity: 566cc
• Capacity Increase vs. Stock: 22%
• Fittings: CNC-Machined Barb Fittings (Fully Welded)
• Radiator Cap Compatibility: OEM Subaru and Mishimoto
• Position: Engine Bay - Direct OEM Location Replacement

Included Components

• 1x Mishimoto Aluminum Coolant Expansion Tank (Polished Silver)
• 1x Mishimoto High-Pressure Radiator Cap
• 1x Mishimoto Lifetime Warranty

Product Description

The Mishimoto MMRT-WRX-08E is a direct-fit aluminum coolant expansion tank engineered for the 2008-2014 Subaru WRX and the EJ255-powered Legacy GT, Outback XT, and Forester XT platforms. The OEM plastic expansion tank used across these vehicles is prone to cracking and failure after years of exposure to repeated heat cycles - a common point of failure on higher-mileage GR-chassis WRX builds. Mishimoto's replacement eliminates that failure mode entirely with TIG-welded all-aluminum construction and fully welded CNC barb fittings, making the entire coolant circuit at the tank's connections impervious to the kind of stress cracking that affects the stock unit over time.

Beyond durability, the MMRT-WRX-08E offers 22% more fluid capacity than the factory tank (566cc total), providing a larger coolant reserve during track sessions, staged pulls, or other high-heat conditions where the cooling system is under sustained load. The polished silver finish is machined to visually complement the Mishimoto Performance Aluminum Radiator (MMRAD-STI-08), making it a natural pairing for a full Mishimoto cooling system build on the GR-chassis WRX. It is also compatible with the stock Subaru radiator cap and the Mishimoto high-pressure cap included in the kit.

Installation is direct-fit into the OEM tank location with no trimming or fabrication required, though owners running the stock "S"-style air intake should note that an aftermarket intake may be needed for proper clearance. This tank is a WRX-specific part and does not fit the WRX STI - STI owners should reference the MMRT-WRX-01E instead. Backed by Mishimoto's Lifetime Warranty.