2010 Subaru Impreza Owner's Manual - Page 332

Maintenance and service 11-13 & Recommended grade and viscosity under severe driving conditions If the vehicle is used in desert areas, in areas with very high temperatures, or is used for heavy-duty applications, use of oil with the following grade and viscosities is recommended. API classification SM (or SL): SAE viscosity No.: 30, 40, 10W-50, 20W-40, 20W-50 Cooling system 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. 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. & 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 following condition occurs, the cooling fan circuit may be defective. . For turbo models, the engine coolant temperature gauge exceeds the normal operating range. Refer to "Temperature gauge" F3-10. . For non-turbo models, the coolant temperature high warning light blinks or illuminates in RED. Refer to "Coolant temperature low indicator light (non-turbo models)/Coolant temperature high warning light (non-turbo models)" F3-20. Check the fuse and replace it if necessary. Refer to "Fuses" F11-46 and "Fuse panel located in the engine compartment" F128. - CONTINUED - & Synthetic oil You can use synthetic engine oil that meets the same requirements given for conventional engine oil. When using synthetic oil, you must use oil of the same classification, viscosity and grade shown in this Owner's Manual, and must follow the oil and filter changing intervals shown in the maintenance schedule. CAUTION . Vehicles are filled at the factory with SUBARU Super Coolant that does not require the first change for 11 years/137,500 miles (11 years/220,000 km). This coolant should not be mixed with any other brand or type of coolant during this period. Mixing with a different coolant will reduce the life of the coolant. Should it be necessary to top up the coolant for any reason, use only SUBARU Super Coolant. If the SUBARU Super Coolant is diluted with another brand or type, the maintenance interval is