2003 Chevrolet Impala Owner's Manual - Page 272
2003 Chevrolet Impala Manual
Page 272 highlights
As in the chart shown previously, if you have the 3400 V6 engine, SAE 5W-30 is the only viscosity grade recommended for your vehicle. You should look for and use only oils which have the API Starburst symbol and which are also identified as SAE 5W-30. If you cannot find such SAE 5W-30oils, you can use an SAE 1OW-30 oil which has the API Starburst symbol, if it's going to be 0°F (-18°C) or above. Do not use other viscosity grade oils, such as SAE 1OW-40 or SAE 20W-50 under any conditions. RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS . . FOR BEST FUEL ECONOMY AND COLDSTARTING,SELECTTHE LOWEST SAE VISCOSITY GRADE OIL FOR THE EXPECTED TEMPERATURE RANGE. HOT WEATHER "F t LOOK FOR T I HS SYMBOL As shown in the following chart, if you have the 3800 V6 engine, SAE 1OW-30 is the viscosity grade recommended for your vehicle. However, you can use SAE 5W-30 if it's going to be colder than 60°F (1 6°C) before your nextoil change. When it's very cold, colder than 0°F (-18"C), you should use an SAE 5W-30 oil. These numbers on an oil container show its viscosity, or thickness. Do not use other viscosity grade oils, such as SAE IOW-40 or SAE 20W-50 under any conditions. 100+ 80,- + 60 t 1~ un + 20 0- 8 - I SAL 5W-30 SAE 1DW-30 PREFERRED above 0°F (-18T) WEATHER DO NOT USESAE 2OW-50 OR ANY OTHER GRADE OIL NOT RECOMMENDED 3800 (Code K) V6 Engine 5-19