1994 Ranger Heating Problem

Ok, I have had problems getting my interior to heat up for some time and have taken several steps to correct it. I noticed that the heater core was leaking so I replaced it. When taken in to get my system flushed, I was told the radiator was bad so I replaced that. I replaced all of the hoses as well and replaced the thermostat (spring side down towards engine). My problem with the truck's tempterature all over the place while driving was fixed, but now I still have no heat to the interior. I have checked the hoses that go to the heater core and they seem to be cold at the firewall hook up. However, the one that comes off the thermostat is very hot where it hooks up to run to the heater core, but gets progressively cooler as you feel the hose to the firewall until the point where you really don't feel any heat at all. I took off the hose off the thermostat and blew through it and was able to blow unobstructively back through to the themostat male plug. I have no idea why I wouldn't have heat, does anyone have any ideas?

Do you have a coolant control valve in the heater hoses? If not I would try purging air from the system. You ussually just have to take the radiator cap off (while cold) and start the engine, turn the heater on so you can bleed the air out of the heater core as well. Run the engine while keeping the coolant topped off in the radiator and overflow tank untill you are at normal operating temperature. There might be a small amount of coolant overflowing but do not worry about it. After it is warm, hot air should be coming out of the vents, if it is not see if both, one or none of the heater hoses feels hot.

Follow the hoses from the heater core connection and see if there is a plastic vacuum operated valve. If the hoses are hot before the valve and cold after the valve see if you have vacuum at the valve. hope this helps if you need further help I am sure myself or someone else can help. be sure to let us know what fixed it if you get if fixed

crasen is right. sometimes it takes awhile to get all the air trapped in the system out. it took 10 minutes on my daughters olds. try bleeding it first.