1994 GMC Suburban Owner's Manual - Page 265

HEAVY DUTY EMISSIONS -GAS ENGINES RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS FOR BEST FUEL ECONOMY AND COLD STARTING, SELECT THE LOWEST SAE VISCOSITY GRADE OIL FOR THE EXPECTED TEMPERATURE RANGE. HOT WEATHER "F tlOO +EO +60 +40 +20 LOOK FOR ONE OF THESE LABELS 7 "C - - +38 - - +27 - - +16 -+4 I - --7 .-18 I €-T I- SAE 1OW-30 PREFERRED above 0°F (-18%) SAE 5W-30 I COLD WEATHER IF NEITHER SAE 5W-30 NOR SAE 1OW-30 GRADE OILS ARE AVAILABLE, SA€ 30 GRADE MAY BE USED AT TEMPERATURES ABOVE 40 DEGREES F (4 DEGREES C). DO NOT USE SAE 1OW-40, SAE 2OW-50 OR ANY OTHERGRADE OIL NOT RECOMMENDED As shown in the chart, SAE IOW-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) beforeyour 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 IOW-40 or SAE 20W-50. 6- 19