For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

California Proposition 65 WarningRear Door Lock Cylinder Replacement
Rear Door Lock Cylinder Replacement
Callout
Component Name
1
Rear Side Door Lock Cylinder Opening Cover Screw Access Plug
Tip: Use a flat-bladed tool to remove the cover.
2
Rear ...
Rear Compartment Lid Rear Hinge Replacement
Rear Compartment Lid Rear Hinge Replacement
Callout
Component Name
Preliminary Procedures
Remove the rear window trim panel. Refer to Rear Window Panel Trim
Replacement.
Remove the rear compartment lid. Refer to Rear Comp ...
Engine Oil Cooler Pipe Replacement (LUW)
Engine Oil Cooler Pipe Replacement
Callout
Component Name
Preliminary Procedures
Drain the cooling system. Refer to Cooling System Draining and Filling.
Remove the exhaust manifold with catalytic converter. Refer to Exhaus ...