Pontiac 2002 Grand Prix Owner's Manual page 279

As in the chart shown previously, if you have the
-
3100 V6 engine, 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.
As shown in the following chart, if you have the
-
3800 V6 engine, SAE 10W 30 is best for your vehicle.
-
However, you can use SAE 5W 30 if it's going to be
colder than 60 _ F (16 _ C) before your next oil change.
-
When it's very cold, you should use SAE 5W 30.
These numbers on an oil container show its viscosity,
or thickness. Do not use other viscosity oils, such
-
as SAE 20W 50.
3800 V6 or 3800 V6 Supercharged Engine
6-17