Originally Posted By: LocoEngr
Or, can I run 0W30 all year and not worry about it?
You certainly can, as others have indicated. Are you running synthetic already, though? If you're running a synthetic, there are few reasons not to switch to a 0w-30, considering the truck is likely past warranty, eliminating any concerns about the GM numbered specifications. If you're running conventional, though, there's not a lot of reason to switch to a synthetic 0w30 unless you're planning on extending your OCIs or do a lot of unaided winter starts.