2010 Cadillac CTS Owner's Manual - Page 311

Vehicle Care Notice: Do not add too much oil. If the engine has so much oil that the oil level gets above the cross-hatched area that shows the proper operating range, the engine could be damaged. 9-11 What Kind of Engine Oil to Use Look for three things: . . American Petroleum Institute (API) starburst symbol GM4718M This vehicle's engine requires a special oil meeting GM Standard GM4718M. Oils meeting this standard may be identified as synthetic. However, not all synthetic oils will meet this GM standard. Use only an oil that meets GM Standard GM4718M. See Engine Compartment Overview on page 9‑6 for the location of the engine oil fill cap. Add enough oil to put the level somewhere in the proper operating range. Push the dipstick all the way back in when through. Notice: Using oils that do not have the GM4718M Standard designation can cause engine damage not covered by the vehicle warranty. . Oils meeting these requirements should have the starburst symbol on the container. This symbol indicates that the oil has been certified by the American Petroleum Institute (API). This vehicle's engine was filled at the factory with a Mobil 1® synthetic oil meeting all requirements for this vehicle. SAE 5W-30 SAE 5W-30 is best for the vehicle. These numbers on an oil container show its viscosity, or thickness. Do not use other viscosity oils such as SAE 20W-50.