GMC Hummer H3 2008 Owner's Handbook Manual page 255

Service and Maintenance
NOTICE
Don't add too much oil. If your
engine has so much oil that the
oil level gets above the upper
mark that shows the proper
operating range, your engine
could be damaged.
Reinsert the dipstick all the way
until it is firmly seated.
. . . 254
Choosing the Right Oil Quality
Use engine oil that meets the
API SL/SM (ILSAC GF-3/GF-4)
rating.
Oils which do not meet these
specifications should not be used.
NOTICE
Failure to use the recommend-
ed oil can result in engine
damage not covered by your
warranty.