2003 Toyota Prius Owners Manual - Page 221

157.Checking the coolant level Oil identification marks Either or both API registered marks are added to some oil containers to help you select the oil you should use. The API Service Symbol is located anywhere on the outside of the container. The top portion of the label shows the oil quality by API (American Petroleum Institute) designations such as SL. The center portion of the label shows the SAE viscosity grade such as SAE 5W-30. "Energy- Conserving" shown in the lower portion, indicates that the oil has fuel-saving capabilities. The ILSAC (International Lubricant Standardization and Approval Committee) Certification Mark is displayed on the front of the container. Look at the see-through coolant reservoir when the hybrid system 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 hybrid system temperature. However, if the level is on or below the "LOW" line, add coolant. Bring the level up to the "FULL" line. To ensure excellent lubrication performance for your engine, the "Toyota Genuine Motor Oil" range is available, which has been specifically tested and approved for all Toyota engines. Please contact your Toyota dealer for further details of the "Toyota Genuine Motor Oil" range. 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, radiator cap and drain cock and water pump. If you can find no leak, have your Toyota dealer test the cap pressure and check for leaks in the cooling system. 214