Heater core gone bad or something else

[blueroo]

In my post about serious engine problems, I mentioned how the temp gauge acts up every now and then and I barely get any heat inside the car. It was suggested on a few boards that I "burp" the lines.

So earlier tonight, I burped the lines. I'm still getting little or no heat inside the car. What makes it really bizzare is both the lines to and from the heater core, after a little while are too hot to grab. You can touch them, but unless you want to hurt yourself, you can't grab them. The blower motor works flawlessly.

I can only think of two possible causes:

1) One of the tubes in the core is partially clogged, reducing the effectiveness of the heater.

2) When I reassembled the heater box, I didn't replace the seals, due in part to the fact the seals aren't available for my heater box. The thing that doesn't make sense to me about that is if you have it set to heat or defrost, you don't get any heat anywhere and the outside of the heater box isn't warm anywhere.

Any suggestions?

 

[pedal2themetal45]

can you feel it moving air? is it blowing out the vent. or the defroster..??

 

[ludwig]

First off, is your heater core getting warm? If not, it is blocked inside. Either have the radiator man boil it out or get a new one. And make shure the coolant is flowing with sufficient volume to heat up the core.

Next I would make sure that the blower is going when the switch goes on. He heater box is not very complicated and those seals are just sheets of open cell foam. You could have a blockage somewhere in the box too, or the tubes to the defroster are torn and otherwise not shooting air to the right place. First and foremost, I would make sure the heater core is getting warm, then go from there.

 

[blueroo]

pedal2themetal45,
I can feel plenty of air coming out of the defroster vents and the floor vent.

Ludwig,
I actually don't know if the heater core itself is getting warm as the only way I can think of getting to it is removing the box. All I know is the lines going to and from are very warm.

 

[ludwig]

The vanes of the core themselves may be pugged up by dust and debris. You can feel the heater core through the vent door on the front of the box. Open it and reach inside.
Or you have to take the front of the box off to get at it. You need a spreader of some sort to get those little clips off the seam holding the two parts of the box together. DON'T just pull them off. SPREAD the clips and retract them, otherwise you will snap the bump off that they engage in. Then you have to get a whole new box (like I did). Either way, you have a blockage in the box, the core or there is no heat exchange.

 

[blueroo]

Ludwig,
The Fairlane box is different than the Mustang box in the fact that the Fairlane's box doesn't come apart. It does have the clips, but it's also riveted. The access plate to the core is between the firewall and the box itself.

By the vent door do you mean the fresh air vent by the kick panel or the floor vent directly over the tunnel hump?

 

[ludwig]

By the vent door do you mean the fresh air vent by the kick panel or the floor vent directly over the tunnel hump?

Yes, the one by then kick panel. But that is for the Mustang. It may be different in the Fairlane.

 

[MustangSix]

The air mixer flap may be stuck.

 

[ludwig]

That's what I was thinking. Or the cable had come off the door and it is pinned open/closed. You can possibly push it back and forth, but I think your best bet is to take the box out and tune it up.

 

[66 Fastback]

I too was thinking the air door/flap may be stuck. That happened on a car I had. The cable moved but the door did not. There was enough slop in the cable and the end of the cable mount was loose so it was not transferring the motion to the lever that openned the door.

You might also disconnect the heater hoses coming into and out of the heater core. Place a water hose up to and see if you can blow water through the core. You might get some crap out. It will at least tell you if the core is plugged.
Doug

 

[woodbutcher]

I would think that if BOTH heater hoses are too hot to touch for long,that the coolant is circulating through the heater core.Check for acumalation of debris in core box and ducts.
Leo