Add some additional reliability and engine bay styling with the Mishimoto Subaru WRX 2002–2007 / STI 2004–2014 Aluminum Coolant Expansion Tank. Stock coolant expansion tanks are prone to failure after years of constant temperature variations. The Mishimoto tank is constructed from durable, TIG-welded aluminum with barbed fittings for optimal durability and longevity. This expansion tank provides a 50% increase in capacity compared to the stock unit. It features a polished finish that will look great in your engine bay, and it matches the Mishimoto Subaru WRX/STI Performance Aluminum Radiator! The Mishimoto Coolant Expansion Tank is engineered for perfect fitment in the 2002–2007 WRX and the 2004–2014 STI!