Bad heater core >>> Check for coolant on the passenger side front, just under the glove compartment floor. Bad head gasket >>> Check for coolant mix with the motor oil.
heater core
If antifreeze is filtering through your ac vents, other toxins could also be coming through. Don't take chances; see a mechanic.
Antifreeze will be leaking in the floorboard on the passenger side, there will be a smell of antifreeze through the vents.
i believe the heater core is leaking, a small pin hole leak can generate a lot of smell.
Most of the time it is caused by a hole in the heater core, do you smell a sweet smell? The sweet smell would be the antifreeze.
More than likely the heater core is leaking.
You have either a cracked heater core or bad heater hoses that are allowing antifreeze to enter into the vehicle............
Most likely the heater core is leaking. Has to be replaced.
Does it smell like burning antifreeze? Usally it means that the heater-core is going bad. If you do not service it it can be a lot worse. You will end up with Anitfreeze all over you passenger side floor board.
the heater core may be plugged up
your heater core is leaking anitfreeze! heatercoreleaks antifreeze into the heater & ac vents causing a burnt spell & oily film on the front window.
Your heater core has failed.