Not much heat

[nickmobile67]

My 67 has factory air, but the heater never seemed to put out much. Over the weekend I changed the heater hoses and hooked them up correctly, with the hose from the intake to the water valve, then to the passenger side of the heater core, and the other hose going to the water pump. They were backwards before. I also installed a new heater valve, a new fitting in the intake with the tube on it (my old one had the tube cut off) a coolant filter in the heater hose, a mechanical temp guage in the back of the intake manifold, and I flushed out the heater core with air. Not to mention the old heater hose had a kink or two in it.
I thought for sure I'd have better heat, but still not much, if any, better! The heater box levers are working fine as far as I can tell. Everyone says thier mustang's put out good heat, so what am I missing? Thanks

 

[mustangdave]

The cardboard box that attaches to your heater box is probably rotten. The cable could appear to move the flapper on the outside but not be doing anything. Replace it with a new plastic one.

 

[pabear89]

Check to make sure the valve is operating, feel the hoses when it has reached running temp to make sure coolant is flowing thru the lines.
sometimes the arm will move but the flapper inside of the valve does not.

PB

Ps. welcome to the board.

 

[nickmobile67]

Thanks for the welcome! The heater valve is new as of last weekend, and I even checked it before I put it in.

What cardboard box are you talking about dave? I don't think 67 uses any cardboard in there?

Anybody have a diagram of how the heater box works? My ford manual dosn't go into detail. If I look inside the recirculated air grate on the side of the heater box I can see it is free of leaves, but is that the heater core or the evaperator core I'm looking at in there? It dosn't get warm with the heat on, but I didn't feel the other side of the box.

 

[Mr44666]

What temp thermostat do you have? maybe it is not allowing your coolant to get hot.

-Dave

 

[nickmobile67]

Thermostat is a new 180, and it's working fine according to my mechanical guage. Both heater hoses get HOT, so there must be flow through the core. I don't get it, where's the hot air going? any way to test the box? all my air doors seem to be working.

 

[crushnut]

What cardboard box are you talking about dave? I don't think 67 uses any cardboard in there?

Anybody have a diagram of how the heater box works? My ford manual dosn't go into detail.

He is talking about the heater plenum, it attaches to the side of the heater box. Ford put in cardboard/paper one, i dont know what they were thinking But i guess it was to save money. The reproductions today are made of a much better plastic.
Like this: http://images.auctionworks.com/fullView.asp?img=http://images.auctionworks.com/hi/61/61286/hp1.jpg

And your Ford manual should go into good detail about the heater box and how it works and goes together. Unless its a chilton or haynes, those manuals suck

 

[nickmobile67]

My manual is a ford reprint, and it shows how the air should flow, but it dosn't go into detail as to how the box itself works. I'll have to look again. Were they still using the cardboard in 67? I thought that was an earlier thing? I'll have to check it out. Both hoses are getting hot so the air must be going somewhere. It comes out the vents, just not too warm!

 

[pabear89]

your hose is hot,but no heat.
Check the connection on the box that controls the fresh air flapper door.
if the flapper does not move, the air will not pass thru the heater core.
sounds like it is stuck in the rec position, allowing only air in cabin to pass thru the heater box.

PB

 

[nickmobile67]

That's what I thougt too, but I can see the door working for the recirculate. All the levers are working on the outside of the box. I though the hot/cold lever might not be working, but I can hear it clunk into both positions. Any way to make sure everything is working?

I looked in my ford manual again, and it shows a nice picture of how the basic heater box works, but not the heat/ac box. Unless I look in the ac section? I'll check now.

 

[frank65]

Thermostat is a new 180, and it's working fine according to my mechanical guage. Both heater hoses get HOT, so there must be flow through the core. I don't get it, where's the hot air going? any way to test the box? all my air doors seem to be working.

I had the same problem with my 65,Turned out to be that when I changed the thermostat it had not seated properly in neck of housing allowing coolannt to by-pass thermostat! Once I fixed that the heater worked fine.

 

[Ozsum67]

Sounds like the heater core may be plugged and not letting the flow circulate. Don't get too hung up on the proper location of the hoses. They will work anyway you put them on a 67.

 

[nickmobile67]

I know the thermostat is ok. I just put a new one in but had the same problem before. I like to use those napa gaskets with the adhesive in one side, it makes installing them a breeze without them slipping down.

I wasn't too worried about the heater hose location, but for what it's worth it's the same way it would have been originally.

If the core was plugged, both hoses wouldn't get warm, would they?

I can reach my hand between the box and the firewall from inside the car and feel both of the tubes from inside, so next time I drive the car I'll have to see if those tubes on the core get warm, and if the box around the core gets warm. Maybe I can feel if heat is leaking out of the box. If it feels like the core is getting warm, the problem must be in the box.

I'm trying to figure out how the reheat door works (vacuum controlled, working) and the hot/cold door (cable controlled, also working) work together.
I don't see why I wouldn't be getting air flow through the core.

 

[pabear89]

Do you get fresh air flow?
the intake could be plugged not allowing air to the inside.
To check if the core is plugged, with the heat temp on high take and squeeze one of the heater hose with pliers. you should hear and feel the coolant pushing thru.

PB

 

[Ozsum67]

I think it would be posible to get some convection or radiant type heating to both hoses without circulation. Why not take the hoses loose from the intake and water pump and see if a garden hose will circulated through the core? That would rule out the plugged up theory.