WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.
Remove the 3 turbocharger oil return pipe bolts (4, 5).
Remove the turbocharger oil return pipe (1).
Remove the turbocharger oil return pipe gasket (2).