1994 Chevrolet Suburban Owner's Manual - Page 270
1994 Chevrolet Suburban Manual
Page 270 highlights
DIESEL ENGINES I I RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS SELECT THE SAE GRADE 011 BASED ON THE EXPECTED TEMPERATURE RANGE BEFORE CHANGE NEXT OIL HOT WEATHER +loo LABEL - - +16 -0 +60 +32 -SAE 30 SAE 15W-40 PREFERRED above 0°F (-18%) 0 - - -18 r -20 -- -29 SAE 1OW-30 \ _____ COLD WEATHER DO NOT USE SAE 1DW-40, SAE 2OW-50 OR ANY OTHER GRADE OIL NOT RECOMMENDED S A E 15W-40 As shown in the viscosity chart, SAE 15W-40 is best for your vehicle. However, you can use SAE low-30 if it's going to be colder than 32°F (0°C) before your next oil change. When it's very cold, below 0°F (-1 8"C), you should use SAE IOW-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