So your Subaru takes really a long time to come up to operating temperature. Or maybe it just runs hot all the time. Chances are it's a stuck thermostat for the radiator. Don't bother replacing it with a parts-store generic 'stat, because they may not have the right hole size for proper flow. Use the factory part. You'll thank us later.
Fits all 2002-21 EJ motor cars, including 2002-2014 Subaru WRX, and 2004-2020 WRX STI.
Gasket sold separately.