1999 Lexus SC 300 Owners Manual - Page 367

ENGINE Coolant type selection Use of improper coolants may damage your engine cooling system. Your coolant must contain ethylene-glycol type coolant for a proper corrosion protection of your engine that contains aluminum components. Use "Toyota Long Life Coolant" or equivalent. In addition to preventing freezing and subsequent damage to the engine, this type of coolant will also prevent corrosion. Further supplemental inhibitors or additives are neither needed nor recommended. Read the coolant container for information on freeze protection. Follow the manufacturer's directions for how much to mix with plain water (preferably demineralized water or distilled water). The total capacity of the cooling system is given on page 331. We recommend to use 50% solution for your Lexus, to provide protection down to about -35_C (-31_F). When it is extremely cold, to provide protection down to about -50_C (-58_F), 60% solution is recommended. Do not use more than 70% solution for better coolant performance. CHECKING THE ENGINE FAN FLUID (SC400 ONLY) NOTICE Do not use alcohol type antifreeze or plain water alone. Park the vehicle at a level spot and look at the see-through 349 reservoir. If necessary, add automatic transmission fluid DEXRONR II or III.