Pontiac 1998 Trans Sport Owner's Manual page 342

What Kind of Engine Oil to Use
Oils recommended
for
your vehicle can be identified by
looking for the "Starburst" symbol. This symbol
indicates that the oil has been certified by the American
Petroleum Institute (API). Do not use any oil which
does not carry this Starburst symbol.
If you change your own
oil, be sure you use oil
that has the Starburst
symbol on the front of the
oil container. If you have
your oil changed for you,
be sure the oil put into
your engine is American
Petroleum Institute certified
for gasoline engines.
You should also use the proper viscosity oil for your
vehicle, as shown in the following chart:
RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS
FOR BEST FUEL ECONOMY AND COLD STARTING,
SELECT THE LOWEST
SAE VISCOSITY GRADE OIL FOR THE EXPECTED TEMPERATURE RANGE.
HOT
WEATHER
7
/
COLD
LOOK
FOR T H I S
SYMBOL
SAE 5W-30
PREFERRED
WEATHER
DO NOT USE SAE 2OW-50 OR ANY OTHER
GRADE
OIL
NOT RECOMMENDED
6-13