Factors such as maintenance, temperatures, driving speeds, vehicle loading, and road conditions affect the wear rate of the tires.

Treadwear indicators are one way to tell when it is time for new tires.
Treadwear indicators appear when the tires have only 1.6mm (1/16 in) or less of tread remaining.
The rubber in tires ages over time.
This also applies to the spare tire, if the vehicle has one, even if it is never used. Multiple factors including temperatures, loading conditions, and inflation pressure maintenance affect how fast aging takes place. GM recommends that tires, including the spare if equipped, be replaced after six years, regardless of tread wear. The tire manufacturer date is the last four digits of the DOT Tire Identification Number (TIN) which is molded into one side of the tire sidewall. The first two digits represent the week (01–52) and the last two digits, the year. For example, the third week of the year 2010 would have a four-digit DOT date of 0310.
Vehicle Storage
Tires age when stored normally mounted on a parked vehicle. Park a vehicle that will be stored for at least a month in a cool, dry, clean area away from direct sunlight to slow aging. This area should be free of grease, gasoline, or other substances that can deteriorate rubber.
Parking for an extended period can cause flat spots on the tires that may result in vibrations while driving. When storing a vehicle for at least a month, remove the tires or raise the vehicle to reduce the weight from the tires.
Tire Rotation
Buying New TiresRemoval Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in
the Preface section.
Disable the SIR System. Refer to SIR Disabling
and Enabling.
Disconnect the negative battery cable. Refer to Battery Negative Cable
Disconnection and Connection.
Remove all related panels ...
Automatic Dimming Rearview Mirror
To adjust the inside rearview mirror, hold the rearview mirror in the center
and move it to view the area behind the vehicle.
For vehicles with an automatic dimming rearview mirror, the mirror will automatically
reduce the glare from the headlamps from behind.
The dimming feature and the indic ...
Definition of Danger, Warning, Caution, and Note
The diagnosis and repair procedures in a GM Service Manual contain both
general and specific Dangers, Warnings, Cautions, Notes or
Importants. GM is dedicated to the presentation of service information that
helps the technician to diagnose and repair the systems
necessary for the proper operat ...