Cadillac 2007 STS Owner's Manual page 382

What Kind of Engine Oil to Use
•
GM4718M
Your vehicle's engine requires a special oil
meeting GM Standard GM4718M. Oils meeting
this standard may be identified as synthetic.
However, not all synthetic oils will meet
this GM standard. Look for and use only an oil
that meets GM Standard GM4718M.
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Notice: If you use oils that do not have the
GM4718M Standard designation, you can cause
engine damage not covered by your warranty.
•
SAE 5W-30
As shown in the viscosity chart, SAE 5W-30 is
best for your vehicle.
These numbers on an oil container show its
viscosity, or thickness. Do not use other
viscosity oils such as SAE 20W-50.
Look for this on the oil container, and use only
those oils that are identified as meeting GM
Standard GM4718M and have the starburst symbol
on the front of the oil container.
Oils meeting these
requirements should
also have the starburst
symbol on the
container. This symbol
indicates that the oil
has been certified by the
American Petroleum
Institute (API).