1999 Subaru Impreza Owner's Manual - Page 270

D The cooling system has been filled at the factory with a high quality, corrosion-inhibiting, year-around coolant which provides protection against freezing down to -33°F (-36°C). For adding, use genuine SUBARU coolant or an equivalent: a mixture of 50% soft water and 50% ethylene-glycol basis coolant. Use of improper coolants may result in corrosion in the cooling system. It is important to maintain protection against freezing and corrosion, even if freezing temperatures are not expected. Never mix different kinds of coolant. D Do not splash the engine coolant over painted parts. The alcohol contained in the engine coolant may damage the paint surface. CAUTION Rubber gaskets HG0115 3. After refilling the reserve tank and the radiator, reinstall the caps and check that the rubber gasket inside the radiator cap is in the proper position. 10-14