2004 Lexus RX 330 Owners Manual - Page 667

ENGINE If the coolant level drops within a short time after replenishing, there may be a leak in the system. Visually check the radiator, hoses, engine coolant filler cap, radiator cap and drain cock and water pump. If you can find no leak, have your Lexus dealer test the radiator cap pressure and check for leaks in the cooling system. Coolant type selection Use of improper coolants may damage your engine cooling system. Only use "Toyota Super Long Life Coolant" or similar high quality ethylene glycol based non- silicate, non- amine, non- nitrite, and non- borate coolant with long- life hybrid organic acid technology. (Coolant with long-life hybrid organic acid technology consists of the combination of low phosphates and organic acids.) "Toyota Super Long Life Coolant" is pre- mixed with 50% coolant and 50% deionized water. This coolant provides protection down to about -35_C (-31_F). CAUTION To prevent burning yourself, do not remove the radiator cap when the engine is hot. NOTICE Do not use plain water alone. 644