Oldsmobile 2003 Silhouette Owner's Manual page 323

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 choose to perform
the engine oil change
service yourself, be sure
the oil you use 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 viscosity chart.
RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS
HOT
WEATHER
~~
COLD
WEATHER
DO NOT USE SAE 1OW-40, SAE 2OW-50 OR ANY OTHER
VISCOSITY GRADE OIL NOT RECOMMENDED
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