I have a 2015 chevy sonic that has a sweet smell coming from the vents when the AC is running, however it is intermittent and the dealership can never find anything wrong with it. Has anyone else had this issue?

 

We also have a 2015 Sonic .

Do not know about Dexcool , but if it was the old green coolant , I would guess leak in the hearer core .

Wyr
God bless