2008 Subaru Impreza Owner's Manual - Page 330

11-14 Maintenance and service od. Mixing with a different coolant will reduce the life of the coolant. Should it be necessary to top up the coolant in your WRX STI for any reason, use only SUBARU Super Coolant. If the SUBARU Super Coolant is diluted with another brand or type, the maintenance interval is shortened to that of the mixing coolant. Do not splash the engine coolant over painted parts. The alcohol contained in the engine coolant may damage the paint surface. If frequent addition of coolant is necessary, there may be a leak in the engine cooling system. It is recommended that the cooling system and connections be checked for leaks, damage, or looseness. & Engine coolant ! Checking the coolant level WARNING Never attempt to remove the radiator cap until the engine has been shut off and has cooled down completely. Since the coolant is under pressure, you may suffer serious burns from a spray of boiling hot coolant when the cap is removed. 1) 2) "FULL" level mark "LOW" level mark & Cooling fan, hose and connections Your vehicle employs an electric cooling fan which is thermostatically controlled to operate when the engine coolant reaches a specific temperature. If the radiator cooling fan does not operate even when the engine coolant temperature gauge exceeds the normal operating range, the cooling fan circuit may be defective. Check the fuse and replace it if necessary. If the fuse is not blown, have the cooling system checked by your SUBARU dealer. Check the coolant level at each fuel stop. 1. Check the coolant level on the outside of the reservoir while the engine is cool. 2. If the level is close to or lower than the "LOW" level mark, add coolant up to the "FULL" level mark. If the reserve tank is empty, remove the radiator cap and refill as required.