Nissan Repair: no heat, nissan sentra, heater hoses

Question
I have 1987 nissan sentra,you put it on heat after motor gets @ right temp ,on heat comes from vents. The heater hoses are in good shape. please help  

Answer
Dave,

Either there is an air pocket in the heater hose or you have a bad blend door.  That is the door that moves between heat and air.  Now, you could have a car that someone has used stop leak in and the heater could be plugged.  Check for this by holding the hose that goes into the firewall and the one that comes out.  If one is hot and the other one is cold the heater core is plugged.  If not and they are both hot then the blend door is stuck.  Lastly, if both hoses are cold then you have an air pocket that has to be purged out.  You can purge the heater by loosening one of the hoses and letting the air escape until antifreeze leaks out and then tightening the hose back up.