*** UPDDATE *** I had emailed Mobil Oil as to why the Mobil Full Synthetic was not Dexos 1 approved: May 7th 2020 Mobil response: I'm not clear, yet, on why this does not carry a Dexos1 approval, but it's on our agenda for a conference call on Monday. You probably won't be the only customer with this question, and I want to be sure we get the right answer. As long as it does not carry a GM license, however, I can not recommend it in any 2011 or newer GM vehicle. May 11th 2020 Mobil response: Happy Monday! We just wrapped up our call and I've got some good news. Mobil Full Synthetic in 0W-20 and 5W-30 will be receiving GM Dexos1 approvals. With the current COVID-19 situation, approvals are slow coming as the testing labs are not considered "essential." So it appears Dexos 1 approval is just delayed due to the backlog at testing/certification labs. I have some quarts that do not have the approval, but I'll have no issue using in a late model GM now that I know what's going on.