1999 Lexus RX 300 User Guide 1 - Page 266

ENGINE If you can find no leak, have your Lexus dealer test the radiator cap pressure and check for leaks in the cooling system. SPARK PLUGS CAUTION To prevent burning yourself, do not remove the radiator cap when the engine is hot. 62R031a 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 243. We recommend 50% solution be used for your Lexus, or a sufficient quantity to provide protection to about -35_C (-31_F). Your engine is fitted with iridium-tipped spark plugs. NOTICE Use only iridium-tipped spark plugs for your engine performance and smooth drivability. NOTICE Do not use alcohol type antifreeze or plain water alone. 251