1973 Dodge Dart Sport No Heat.

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Thats not a manual valve, its vacuum operated. Never mind the two things in the cowl. Those are 73 only knox sensors I believe and usually run to the distributor. You have two vac lines coming out of the firewall to the left of the heater hoses. One runs to the heater control valve and the other to the vacuum amplifier (round black sphere on the left). Make sure the vacuum amplifier has vacuum on it. It should have a larger hose that probably runs to the intake or the base of the carb. Also, manually try operating the heater control valve. It may just be stuck.
 
There are no hoses connected to the valve. Doesn't look like there are any hoses going to the heater core at all.
My pictures are from my '72 Dart.

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Upon a second look I see that there is in fact a manual valve in there. Looks like someone bypassed the original setup.
 
MoparMike1974 said:
Upon a second look I see that there is in fact a manual valve in there. Looks like someone bypassed the original setup.
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Yes, they bypassed the original valve and added a manual in line valve. Both hoses go to the firewall and I assume to the heater core but haven't gotten that far yet. I need to get a chassis manual for the car.
 
The vacuum valve only stops water flow, so if it is bypassed the heater will still work. Looks like the manual valve someone added is in the “open“ position, so that should not stop water flow.
 
Thank you. Oh, and that was where the original antifreeze sticker was.
 
Mike69cuda said:
The vacuum valve only stops water flow, so if it is bypassed the heater will still work. Looks like the manual valve someone added is in the “open“ position, so that should not stop water flow.
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Yes I bought the car in Arizona so they had the manual heater valve closed. I opened it. One more question. I have factory AC. Do I have to remove the incide AC vent below the dash to get to the heater box?
 
Take out the glove box and you can see most of the heater controls. The ac vent doesn’t buy you much.
 
With the engine running, check to see if the air comes out of the windshield when in defrost and the floor when in heat. That will tell you if the vacuum is hooked up.
 
May I respectfully suggest you actually get a coolant temperature.
Get the engine up to 'running" temp, if you have a heat gun, shoot the top rad hose temp. If you need to go borrow the wife's/neighbors meat probe, same think, stick it into coolant at rad cap.
The coolant temp needs to be +160* to get "warm" air outta the heater duct.
If the thermostat is stuck open, the heater hoses will feel warm, but not near hot enuff.
For decent winter heat, 180* is normal to get regular heat, the 195* thermostat is for really cold climate where the ambient air going into the heater is frigid/polar.
Just before you tear the dash apart, make sure the coolants hot enuff.
Go check the temps on your daily driver for comparison .
Good luck .
 
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There are 2 vacuum pods under the dash, they need to be functioning. One is next to the vent pass side. The other is on the top middle. Two nuts hold the A/C vents, yes, doesn't give you much and with the glove compartment out, you can see most of it. If you end up removing the heater box or A/C box, you might as well get the kits from DETROIT MUSCLE and rebuild them, they probably need it, mine did.
 
inertia said:
May I respectfully suggest you actually get a coolant temperature.
Get the engine up to 'running" temp, if you have a heat gun, shoot the top rad hose temp. If you need to go borrow the wife's/neighbors meat probe, same think, stick it into coolant at rad cap.
The coolant temp needs to be +160* to get "warm" air outta the heater duct.
If the thermostat is stuck open, the heater hoses will feel warm, but not near hot enuff.
For decent winter heat, 180* is normal to get regular heat, the 195* thermostat is for really cold climate where the ambient air going into the heater is frigid/polar.
Just before you tear the dash apart, make sure the coolants hot enuff.
Go check the temps on your daily driver for comparison .
Good luck .
Click to expand...
I measured engine block heat at about 215 with a thermal gun. Here is a pic of the two heater hoses going into the firewall.

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CRUZE 418 said:
There are 2 vacuum pods under the dash, they need to be functioning. One is next to the vent pass side. The other is on the top middle. Two nuts hold the A/C vents, yes, doesn't give you much and with the glove compartment out, you can see most of it. If you end up removing the heater box or A/C box, you might as well get the kits from DETROIT MUSCLE and rebuild them, they probably need it, mine did.
Click to expand...
OK. Thanks.
 
if you move the lever from cold to hot and nothing happens check that the cable outer is clamped at the heater box end. if it isn't the lever just slides the outer along the inner and it doesn't open the appropriate flap in the heater box

if you have aircon box and no vacuum connected up (check as above) and then

the heater will default to warming your feet

if you want it on the screen find the vacuum pod down low closest to the kick panel
pull the actuator rod as far as it will go towards the centre of the car
put a cable tie tight around it tight up against the vacuum pod to stop it moving back

you have just forced the door open that causes the warm air that was bothering your feet to be directed up out the front of the unit into the plastic conduit up to the dash vents

if the cardboard and foil tubes are in place you should now have screen demist

Dave
 
Also, on my '72, actuator by the kick panel sticks, I have to reach down and give the rod a little tug, something isn't quite free, I just live with it.
 
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