1995 Buick Regal Owner's Manual - Page 219

RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS FOR BESTFUELECONOMYANDCOLDSTARTING,SELECTTHELOWEST SAL VISCOSITY GRADE OIL FOR THE EXPECTED TEMPERATURE RANGE. - HOT WEATHER "F "C -100+BO- - +38 - +27 +60--+16 LOOK FOR THIS SYMBOL As shown in the chart, SAE 1OW-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) before your 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 20W-50. +40--+4 +20---7 0---18 SAE 1OW-30 PREFERRE0 above 0°F SALSW-30 (-18OC) COLD WEATHER DO NOT USE SAE 2OW-50 ANY OTHER OR GRADE OIL NOT RECOMMENDED 3.8L L27 (Code L) Engine 6-11