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:
Passing
More passing distance is needed when towing a trailer. Because the rig is longer, it is necessary to go farther beyond the passed vehicle before returning to the lane. ...
Voice Pass-Thru
Voice pass&-thru allows access to the voice recognition commands on the cell
phone. See your cell phone manufacturer's user guide to see if the cell phone supports
this feature.
To access ...
Customer Assistance Offices (U.S. and Canada)
GMC encourages customers to call the toll-free number for assistance.
However, if a customer wishes to write or e-mail GMC, the letter should be addressed to:
United States
GMC Customer Assistance ...





