Engine Oil Additives/Engine Oil Flushes
Do not add anything to the oil.
The recommended oils with the dexos specification and displaying the dexos certification mark are all that is needed for good performance and engine protection.
Engine oil system flushes are not recommended and could cause engine damage not covered by the vehicle warranty.
See also:
Roadside Assistance Program
U.S.: 1-888-881-3302
TTY Users (U.S.): 1-888-889-2438
Canada: 1-800-268-6800
Mexico: 01-800-466-0801
As the owner of a new GMC, you are automatically enrolled in the Roadside Assistance program.
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Service Publications Ordering Information
Service Manuals
Service Manuals have the diagnosis and repair information on the engines, transmission, axle, suspension, brakes, electrical, steering, body, etc.
Service Bulletins
Service Bulletin ...
Federal Communications Commission (FCC) Rules and with Industry Canada Standards
See Radio Frequency Statement on page 13‑21 for information regarding Part 15
of the Federal Communications Commission (FCC) Rules and with Industry Canada Standards
RSS-GEN/210/220/310. ...