that is prob ur water pump or thermostat
The front expansion valve is clogged.
Get the air out of your heater core.
Your heater will blow cold air only.
possible clogged or damaged heater core
THE CAUSE for this is that when your cold air is on the petrol is used to create air. and that is how cars create cold air
Check your radiator coolant level. On some cars, low coolant will let air bubbles into the heater core which can result in intermitant cold air bursts.
I assume your car heater is blowing cold air, when the heater is on. It seems that, you have air on your coolant. that air pockets blocks the cooland to travel through your heater. it may be a sign of a bigger problem such as blown head gasket in the old cars, such acura legend
The most common reason the heater is blows cold air on a 1999 Ford Winstar is a bad thermostat or blocked heater core.
The heater may blow cold air instead of warm air due to issues such as low coolant levels, a malfunctioning thermostat, a clogged heater core, or a faulty blend door. These problems can prevent the heater from properly warming the air before it is blown into the car.
The most likely cause is that your air mix door has malfunctioned, and will not change from ac to heat, but it is possible that your heater core has become blocked, or that there is a water valve in the line that has become stuck.
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.
It doesn't really blow it out it just warms the cold air.