2003 Pontiac Grand Prix Owner's Manual - Page 246
2003 Pontiac Grand Prix Manual
Page 246 highlights
RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS HOT WEATHER LOOK FOR T I HS SYMBOL . As in the chart shown previously, if you have the 3100 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 SA€ 5W-30. I f you cannot find such SAE 5W-30 oils, you can use an SAE IOW-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 IOW-40 or SAE 20W-50 under any conditions. As shown in the following chart, if you havethe 3800 V6engine, SAE IOW-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 (16°C) before your next oil change. When it is very cold, colder 5W-30 oil. than 0°F (-18°C) you should use an SAE These numberson anoil container show its viscosity, or thickness. Do not use other viscosity grade oils, such as SAE 1OW-40 or SAE 20W-50 under any conditions. 1 - 1 1 r SAE S'W.-30 RECOMMENDED SAE IOW-30 ACCEPTABLE IF 5W-30IS NOT AVAILABLE COLD WEATHER DO NOT USE SAE 1OW-40, SAE 2OW-50 OR ANY OTHER VlSCOSlN GRADE OIL NOT RECOMMENDED 3100 V6 Engine 5-2 1