2006 Chevrolet Corvette Owner's Manual - Page 298

What Kind of Engine Oil to Use Look for two things: • GM4718M Your 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. 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. 5-22