Onstar.com
The website provides access to account information, manages the OnStar subscription, and allows viewing of videos of each service.
Get subscription plan pricing and sign up for OnStar Vehicle Diagnostics. Click on the “My Account” tab on the home page.
See also:
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 ...
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.
...
Engine Overheating
If the vehicle has the Duramax® Diesel engine, see the Duramax Diesel Supplement for more information.
The vehicle has several indicators to warn of engine overheating.
There is a coolant temperatu ...