Chevrolet GMC 2002 Owner's Manual Supplement page 49

What Kind of Engine Oil to Use
Look for these two things:
D
- -
CH 4 or CG 4
Oils designated as API CH
-
your vehicle. The CH
appear either alone, together or in combination with
other API designations, such as API CH
- -
CG 4/SH or CH 4/CG
These letters show American Petroleum Institute (API)
levels of quality.
NOTICE:
If you use oils that don't have one of these
designations either CH
cause engine damage which is not covered by
your warranty.
6-20
- -
4 or CG 4 are best for
-
4 or CG 4 designations may
-
4/SJ,
-
4/SJ.
- -
4 or CG 4, you can
D
-
SAE 15W 40
As shown in the viscosity chart, SAE 15W
is best for your vehicle. However, you can use SAE
-
10W 30 if it's going to be colder than 32
before your next oil change. When it's very cold,
_ _
-
below 0 F ( 18 C), you should use SAE 10W
to improve cold starting. Also, SAE 30 may be used
at temperatures above freezing, 32
These numbers on the oil container show its
viscosity, or thickness. Do not use other viscosity
oils such as SAE 10W
You should look for this on the oil container, and use
only those oils that display the logo.
GM Goodwrench R oil of the recommended viscosity
grades meets all the requirements for your vehicle.
-
40
_ _
F (0 C)
-
30
_ _
F (0 C).
- -
40 or SAE 20W 50.
-
This doughnut shaped
logo (symbol) is used
on most oil containers
to help you select the
correct oil. It means that
the oil has been certified
by the American
Petroleum Institute.