No! Thermostat.
heater core possibly plugged and leaking
Probably need to add antifreeze. Check the Radiator not the overflow tank. If you are low on antifreeze it will not circulate through the heater core.
Probably - your head gasket is blown. Antifreeze will be coming out of the tail (exhaust) pipe.
heat core. leak. thermostat. no antifreeze.
Check Antifreeze level..make sure there are no leaks under the vehicle.
Most likely cause is low coolant. Check your antifreeze level.
if antifreez is blowing into cab, u need to replace the heater core the core has a hole in it. thses are not repairable and they are cheap to buy
Leak in heater core. Replace core.
The heater coil probably has a leak causing steam and vaporized antifreeze to be released into the vents. Is it using coolant?
The front expansion valve is clogged.
antifreeze keeps your car from overheating, it flows thru your radiator hose, without it your motor would blow
It doesn't really blow it out it just warms the cold air.