2003 Lexus GX 470 Owners Manual - Page 436

ENGINE CHECKING THE ENGINE COOLANT LEVEL 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. CAUTION To prevent burning yourself, do not remove the radiator cap when the engine is hot. Coolant type selection " 1 Reservoir cap 2 "F" (upper) line 3 "L" (lower) line Look at the see−through coolant reservoir when the engine is cold. The coolant level is satisfactory if it is between the"F" and "L" lines on the reservoir. If the level is low, add ethylene−glycol type coolant for a proper corrosion protection of aluminum components. The coolant level in the reservoir will vary with engine temperature. However, if the level is on or below the "L" line, add coolant. Bring the level up to the "F" line. Always use ethylene−glycol type coolant for a proper corrosion protection of aluminum components. See information in the next column. 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. We have used "Toyota Genuine Long Life Coolant" in your Lexus vehicle. In order to avoid technical problems, we strongly recommend using "Toyota Genuine 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 413. 422