Pontiac Sunbird Owner's Manual page 201

Service & Appearance Care
Engine Oil
(CONX)
Just fdl it enough to put the level
somewhere in the proper operating
range. Push the dipstick all the way
back in when you're through.
2.0L L4:
Adding Engine Oil
3.1L V6:
Adding Engine Oil
What Kind of Oil to Use
Look for Three Things:
SG
"SG" must be on the oil container,
either by itself or combined with other
quality designations, such as
"SGJCC," "SGJCD," "SF, SG, CC,"
etc. These letters show American
Petroleum Institute (API) levels of
quality.
If you use oils that don't have the
"SG" designation, you can cause
engine damage not covered by your
warranty.