2003 Honda Civic Owner's Manual - Page 205
2003 Honda Civic Manual
Page 205 highlights
Engine Oil The SAE number tells you the oil's viscosity or weight. Select the oil for your vehicle according to this chart. 5W-20 oil is formulated for yearround protection of your Honda, to improve cold weather starting, and to help your engine use less fuel. Synthetic Oil You may use a synthetic motor oil if it meets the same requirements given for a conventional motor oil: it displays the API Certification Seal, and it is the proper weight as shown on the chart. When using synthetic oil, you must follow the oil and filter change intervals given in the maintenance schedule. Additives Your Honda does not require any oil additives. Additives may adversely affect your engine's or transmission's performance and durability. Ambient Temperature 204 Maintenance