Check the heater core, it is probably bad. It could be heater hose connections to the heater core, but I would bet on the heater core going bad.
Check for a line leak to your heater core or a leak in the heater core it self. Usually it is under the dash on passinger side.
A part or gasket has failed.
The heater coil probably has a leak causing steam and vaporized antifreeze to be released into the vents. Is it using coolant?
probably the coolant tube under the manifold. it is only available from the dealer
A part has failed. Find where the leak starts, and fix that part.
i believe the heater core is leaking, a small pin hole leak can generate a lot of smell.
you have leak somewhere
in my experience it is a slight leak in heater core it will be antifreeze causing this replace heater core and problem will be fixed
It could be a small leak that you're just not seeing or it may be ingesting the coolant through a bad head gasket or cracked block/head.
That is probably antifreeze steam. Your heater core is a small radiator used to heat your car. The engine heats the antifreeze and circulates it through the heater core. Your blower blows heat through the core (radiator) into the car, and warms you. If the core gets a small leak, it will put out steam.
The "antifreeze smell out the AC vents" would mean only one thing, you have a small leak in the heater core.
The smoke is most likely a leak in prestone. Is the antifreeze level going down? OR, if the smoke has stopped, then something blew on the a/c. and now there is no more freon.