Nissan Repair: heater, heater hoses, radiator hose

Question
I have a 1992 Maxima GXE and the heater is not working properly. That is, the heat only comes out warm from the heater. From previous post on your website I loosened up the uppper radiator hose to let out air and that helped some what. Unfortunately the same problem returns about 3 to 4 days later.  I noticed when I did loosen the upper hose that there was very little flow coming thru the line.  That is, there is no way to bleed all the air out of the line because of the lack of flow. I am not familiar with how thw system is suppose to work so I don't know what to look for.  Any ideas?  

Answer
Russ,

If the flow is insufficient you might have a blocked heater core.  This old someone could have used stop leak in the engine and that will plug the heater core.  You might try to remove the heater hoses at the engine and blackflush the core.  If there is insufficient water flow you will have to replace the core.