I have a 2012 GMC Duramax LML that I just got out of the shop for a head gasket change and CP3 upgrade and I noticed on start up in the morning I’m getting a puff of white smoke, is this normal?
Yes, it’s normal for a straight piped truck to white smoke a tad on start up. It’s bc the egr isn’t active and the intake air heater can’t get it hot enough.