My 96 honda civic ex 2 door 5 speed blows cold air. The heater core is hot as are the appropriate hoses, the radiator hoses are hot. Thermostat is good. The car is running normal temperature. When selected, the air comes out of the vents selected. The air is cold regardless of the temperature control setting. Its as if air is not going over the heater core. What could cause this. Please help, I'm freezing!!

Are both the hoses the in and out connected near the firewallhot or only one side you know that it is flowing throu enough to the core because the cores hot if so have you tried to flush the heater core with a garden hose connected to the heater hose so the water moves both ways into the core hoses? Effectivly flushing small rust or contaminants OK that done you have to move some duflopper inside core box houseing itself
I recently found my waterpumpsvains were rotted off so it wasn't pumping into my core a replacement pump solve my heating needs happy but it took me like 4 hours just to find out also my bypass was stopped up and the passeg under my manidold was stopped up it all works now but I had to take a wire and prog the rust junk out then squish water from a hose throu lines etc

Thanks. Yes I have checked all that. For some reason which I can't figure out, the air is not being forced over and through the heater core, hence not heating the air. What "duflopper" thing are you talking about in the heater core box? What does it do and how do I get to it? Thanks

I said to move the duflopper an over simplified suggestion I would remove the fan from the bottom of the core houseing under the glove box see if the fan is all right see if any birds nests or rats nests are inside this houseing run yer hand inside it if so clean it out with yer hand physically inspect the fan is it broken? I can't see you not getting some heat some way is thar a vacume line comeing into the car fron under the hood ? Is it connected to the manifold is thar a heat control valve on the hose if not then its regulated in the cores houseing ductwork I suppose thar has got to be some way of figuring this out and taking the dash apart it the last thing to do be certain thar is sufficient heat in the core itself and that the fan is doing what it should be aside from that you will have to go this one alone my friend I feel for you I went all winter last winter with no heater and your in a much colder invionment I think OK here is a silly suggestion if your cars parked at yer house and you take the fanout of the bottom of the core houseing then if you have a small house fan withna dorp cord attached and you place the fan up to the opening were the normal blower was incerted with the fan running off the extension and the nmoter running will the small fan pull heat into the car if so the it has to be the ductwork in the area left of the core directly under the dash ?know what I mean?

Check again the forced movement of coolent throuthe hose by starting the motor the removing one of the hheater hoses id the water swooshing out or is it just simply draining from the opening drainning is not swooshing by the pump it has to physically pump fourth to flow enough ofr the core will be hot for a secon then cooldown to no working heat OK? Be aware you have to asses the flow factor OK

Thank you again. I think your answer leans toward the fan maybe not working. The fan is working perfectly, and the heater core housing is very warm to the touch. The problem is that cold air is coming out of the vents. Everything works, it's just cold air coming out. Is there some kind of door/valve thing that is not directing the air to blow over the heater core, and if so, where is it, how do I check it, and how do I fix it? Thanks!

There is a door,the blend door I think its called. It covers the heater core when ac is called for and covers the ac part when heat is called for. Seems you'rs is stuck in the ac posistion.there mostly vacume operated,but some have actuators,that move them.look under the dash by the heater core box for a vacume line that's off or broken.theres usually a round vacume pod,that the vacume line hooks to,the door after being found can be moved manually .good luck and hope it helps.