GMC 2002 Sierra - Manual (Page 384)

6-17
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 Goodwrench
R
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.