1999 Lexus SC 300 Owners Manual - Page 366

ENGINE Look at the see-through coolant reservoir when the engine is cold. The coolant level is satisfactory if it is between the"FULL" and "LOW" 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 "LOW" line, add coolant. Bring the level up to the "FULL" line. Always use ethylene-glycol type coolant for a proper corrosion protection of aluminum components. See information in the next column. 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 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. 348