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:

Vehicle Care
California Proposition
65 WarningSecondary Camshaft Intermediate Drive Chain Tensioner Replacement - Left Side Valvetrain Camshaft
Removal ProcedureRemove the engine front cover. Refer toEngine Front Cover Replacement.Remove the left bank secondary camshaft drive chaintensioner. Refer toSecondary Timing Chain Tensioner Removal - Left Side.Installation ProcedureInstall the left bank secondary camshaft drive chaintensioner. Refer ...