Originally Posted by cjhutch
The official answer is to use an oil that meets GM LL A 025 spec. Not sure if it's the same in Canada, but the two most common oil that meet the spec here in the states are Mobil 0W-40 and Catrol Syntec 5W-30 (Made in Germany) which is only available from AutoZone. There are also other oils that meet the spec from Motul, Total, and Amsoil.
Good answer. However your manual should state 0W-30 or 0W-40. The last year or two 5W-30 and 5W-40 have been added.
Mobile 1 0W-40 is your best bet all around--reasonably priced, easy to get, and probably the best oil out of all of them.
03' SS Linear Cosmic Blue, 109k mi., gone
06' SC Aero Auto Fusion Blue, BSR tuned, 94k gone.
09' SS Aero XWD Auto
Carbon Gray, Black Premium Leather, VTuned, 30% tint.