have you tried contacting your dealer about this? they might be able to take a look and tell you if it’s within normal limits or needs adjustment. Could save you some worrying!
have you considered calling a local GM dealer? They might be able to give you the exact specs for your model. Just a thought, might save you some headache
dang, that’s frustrating. Good on you for helping out even when you were annoyed. Maybe next time he’ll think twice before ignoring car issues. Does he know basic car maintenance stuff? Could be worth teaching him if not.