It doesn't really blow it out it just warms the cold air.
Your heater will blow cold air only.
1) low coolant? 2) bad thermostat? 3) system airbound? 4) heater core plugged? 5) heater control cable broken?
The front expansion valve is clogged.
it wont blow heat itll blow cold air
you are low on coolingliquid !
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
No, not if it's on a heat setting. Most home thermostats have a "Fan" setting that will blow cold air if the attic is cold.
heater core possibly plugged and leaking
No! Thermostat.
One of the reasons a 2000 Jeep Cherokee heater would randomly blow cold air and then hot air and then cold might be that there is a problem with the hot/cold duct. The air or a vent might be inadvertently blowing periodically.
you may not have the heater water hoses plugged in