GMC 1994 Yukon Owner's Manual page 271

DIESEL ENGINES
SELECT THE SAE GRADE OIL BASED O N
THE EXPECTED TEMPERATURE RANGE
BEFORE NEXT OIL CHANGE
HOT
WEATHER
:F
t
100
;C
-
+38
+60 - - + 1 6
+32
- -
0
0
-
-
-18
-20
-
-
-29
COLD
SAE 1OW-30
I I
SAE
I
30
SAE
15W-40
PREFERRED
above 0°F
(- 1 8°C)
WEATHER
DO NOT USE SAE 1OW-40, SAE 2OW-50 OR
ANY OTHER GRADE OIL NOT RECOMMENDED
SAE 15W-40
As shown in the viscosity chart, SAE 15W-40 is best for your vehicle.
However, you can use SAE 1OW-30 if it's going to be colder than
32°F (OOC) before your next oil change. When it's very cold, below
0°F (-18"C), you should use SAE I OW-30 to improve cold starting.
Also, SAE 30 may be used at temperatures above freezing, 32°F (0°C).
These numbers on the oil container show its viscosity, or thickness. Do
not use other viscosity oils such as SAE 10W-40 or SAE 20W-50.
6-25