I had my chevy cruze since 2015 and the heater always worked perfect which stills does in a way but last year it smoked one and I thought it was the fan running weird due to the extreme temperature of the polar vortex in chicago. come this year it's been smoking and having the burning smell of the coolant for a few minutes then goes back to normal. After doing my research theres a leak that's cause it to burn off the coolant that has leaked out but I can't find the leak anywhere. But when I check under the floor mat its damp with the smell of coolant but no visible clue of where it's coming from. I seen alot of thread but I still can't find the problem and I don't want to bring it in and they replace the heater core and it's still leaking somewhere. Any new or recent clues anybody.