2007 Chevrolet Cobalt Owner's Manual - Page 291

However, not all synthetic oils will meet this GM standard. You should look for and use only an oil that meets GM Standard GM4718M. Notice: If you use oils that do not have the GM4718M Standard designation, you can cause engine damage not covered by your warranty. • SAE 5W-30 As shown in the viscosity chart, SAE 5W-30 is best for your vehicle. These numbers on an oil container show its viscosity, or thickness. Do not use other viscosity oils such as SAE 20W-50. Oils meeting these requirements should also have the starburst symbol on the container. This symbol indicates that the oil has been certified by the American Petroleum Institute (API). You should look for this on the oil container, and use only those oils that are identified as meeting GM Standard GM4718M and have the starburst symbol on the front of the oil container. Your vehicle's engine is filled at the factory with a synthetic oil which meets all requirements for your vehicle. Substitute Engine Oil: When adding oil to maintain engine oil level, oil meeting GM Standard GM4718M may not be available. You can add substitute oil designated SAE 5W-30 with the starburst symbol at all temperatures. Substitute oil not meeting GM Standard GM4718M should not be used for an oil change. Engine Oil Additives Do not add anything to the oil. The recommended oils with the starburst symbol that meet GM standards are all you will need for good performance and engine protection. 291