1996 GMC Sonoma Owner's Manual - Page 235

As shown in the chart, 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. When to Change EngineOil See if any one of these is true for you: 0 Most trips are less than 5 to 10 miles (8 to 16 km). This is particularly important when outside temperatures are below freezing. NOTICE: Use only engine oil with the American Petroleum Institute CertifiedFor Gasoline Engines "Starburst"symbol. Failure to use the recommendedoil can result in engine damage not covered by your warranty. GM Goodwrench@ oil meets all the requirements for your vehicle. 0 Most trips include extensive idling (such as frequent driving in stop-and-go traffic). You operate your vehicle in dusty areas or off-road frequently. You frequently tow a trailer. The vehicle is used for delivery service, police, taxi or other commercial application. 0 0 0 Engine Oil Additives Don't add anything to your oil. Your G M dealer is ready to advise if you think something should be added. Driving under these conditions causes engine oil to break down sooner. If any one of these is true for your vehicle, then you need to change your oil and filter every 3,000 miles ( 5 000 km) or 3 months -- whichever occurs first. I f none of them is true, change the oil and filter every 7,500 miles (1 2 500 km) or I2 months -- whichever occurs first. Driving a vehicle with a fully warmed engine under highway conditions causesengine oil to break down slower. 6-13