1993 Buick Regal Owner's Manual - Page 224

What Kind of Oil to Use: Look for threethings: SG "SG" must be on the oil container, either by itself or combined with other quality designations, such as "SG/CC," "SG/CD," "SF,SG,CC," These letters etc. show American Petroleum Institute (API) levels of quality. - RECOMMENDED SAE VISCOSITY GRADE ENGINE O S l FOR BEST N E 1 F""""7Y AND COW STARTING, SELECT R E LOWEST - JIL FOR THE EXPECTED TEMPERATURE RANGE. SAE VlSCOSlTT C ~. . - HOT WEATHER 7 "F t 100 + 80 t 60 + 40 + 20 0 If you have the 3.8L engine use: SAE 1OW-30 SAE 1OW-30 is best As shown in the viscosity chart, for your vehicle. However, you can use SAE 5W-30 if it's going tobe colder than60°F (16 "C) before your next oil change. When it's very cold, below O°F (-18OC), you should use SAE 5W-30. COLD WEATHER IF NEITHER SAE 5W-30 NOR SAE 1OW-30 GRADE OILS ARE AVAILABLE, SAE 30 GRADE MAY BE USED AT TEMPERATURES ABOVE 40 DEGREES F (4 DEGREES 6). DO NOT USE SAE 1OW-40, SAE 2 IR ANY OTHER GRADE OIL NOT REO 3ED 222