Chevrolet 2007 Cobalt Owner's Manual page 291

However, not all synthetic oils will meet this
GM standard. You should look for and
use only an oil that meets GM Standard
GM4718M.
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.
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).
You should 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.
Your vehicle's engine is filled at the factory with a
synthetic oil which meets all requirements for
your vehicle.
Substitute Engine Oil: When adding oil to maintain
engine oil level, oil meeting GM Standard
GM4718M may not be available. You can add
substitute oil designated SAE 5W-30 with the
starburst symbol at all temperatures. Substitute oil
not meeting GM Standard GM4718M should not be
used for an oil change.
Engine Oil Additives
Do not add anything to the oil. The recommended
oils with the starburst symbol that meet GM
standards are all you will need for good
performance and engine protection.
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