1998 Lexus LS 400 Owners Manual - Page 335

ENGINE Engine coolant selection Your coolant must contain ethylene-glycol antifreeze. In addition to preventing freezing and subsequent damage to the engine, this will also prevent corrosion. Further supplemental inhibitors or additives are neither needed nor recommended. Read the antifreeze container for information on freeze protection. Follow the manufacturer's directions for how much to mix with water. The total capacity of the cooling system is given on page 325. We recommend 50% solution be used for your Lexus, or a sufficient quantity to provide protection to about -35_C (-31_F). NOTICE Do not use alcohol type antifreeze or plain water alone. SPARK PLUGS Your engine is fitted with iridium spark plugs. NOTICE Use only iridium spark plugs for your engine performance. 335