2002 Oldsmobile Alero Owner's Manual - Page 254

As in the chart shown previously, SAE 5W-30 is best for your vehicle. However, you can use SAE 10W-30 if it's going to be 0 F (-18 C) or above. These numbers on an oil container show its viscosity, or thickness. Do not use other viscosity oils, such as SAE 20W-50. _ _ NOTICE: Use only engine oil with the American Petroleum Institute Certified For Gasoline Engines starburst symbol. Failure to use the recommended oil can result in engine damage not covered by your warranty. GM GoodwrenchR oil meets all the requirements for your vehicle. If you are in an area where the temperature falls below -20 F (-29 C), consider using either an SAE 5W-30 synthetic oil or an SAE 0W-30 oil. Both will provide easier cold starting and better protection for your engine at extremely low temperatures. _ _ 6-17