Heat not working, no hot air

Hi,

If both heater hoses are getting hot, then the heater core isn't plugged. That leaves the blend air door. The blend air door is what controls the air temp entering the vehicle. What I suggest is to remove it and inspect it to see if it is working. Take a look at this link. It explains in general how one is replaced. Additionally, it explains what goes wrong with them

https://www.2carpros.com/articles/replace-blend-door-motor

and

https://www.2carpros.com/articles/car-heater-not-working

Here are the directions for the removal and replacement of the one specific to your vehicle. The attached pic correlates with the directions.

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1994 Lincoln Town Car V8-281 4.6L SOHC
Blend Door
Vehicle Heating and Air Conditioning Air Door Service and Repair Procedures Blend Door
BLEND DOOR
Doors

A/C Air Temperature Control

Removal

1. Remove the heater air plenum chamber from the vehicle as outlined.

2. Remove blend door actuator crank arm.

3. Move the A/C air temperature control door to the full heat position. Remove one screw retaining the A/C air temperature control door to the crank arm.

4. Remove the A/C air temperature control door from the crank arm and remove the door from the dash panel inlet opening of the heater air plenum chamber.

Installation

1. Position the A/C air temperature control door through the dash panel inlet opening of the heater air plenum chamber and to the door crank arm.

2. Install one screw to attach the A/C air temperature control door to the crank arm.

3. Check the A/C air temperature control door for freedom of movement. Correct any existing sticking, binding or grabbing condition.

4. Install A/C electronic door actuator motor if removed.

5. Install the heater air plenum chamber in the vehicle as outlined.

6. Check the system for proper operation.

Let me know if this helps or if you have any questions.

Take care,
Joe

Check if both heater core hoses are getting hot. If they are, check to make sure the blend air door is working.

I would check again for coolant loss. Look underneath the intake in the valley of the cylinder heads and see if you see coolant. These motors have a redesigned intake manifold.

You could have a bad blend door actuator.

Hi and thanks for using 2CarPros.

This vehicle does not have a heater control valve. In its place is a blend air door actuator. The heater core in the vehicle always circulates coolant, so it is always hot. What determines if you get heat into the vehicle is the blend air door. In one position, it closes off heat and in the other, it allows heat to enter the cab.

The blend air door is actuated by a vacuum servo. However, if you are not getting heat, confirm that both heater core hoses are getting hot when the engine is at operating temperature and the heater is on high. If they are, the actuator is the problem. If only one of the hoses is hot, suspect a plugged heater core.

Here is a quick link to look through. It discusses common causes of not getting heat.

https://www.2carpros.com/articles/car-heater-not-working

Here is a link that shows in general how to replace a blend air door actuator:

https://www.2carpros.com/articles/replace-blend-door-motor

If you determine the problem is the actuator, here are the directions specific to your vehicle for replacing the actuator which I mentioned. Note that the actuator on your vehicle is vacuum actuated. Make sure it is getting vacuum.

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WITH AUTOMATIC TEMPERATURE CONTROL
REMOVAL
1. Disconnect the battery ground cable.
2. Disconnect the glove compartment door stop (one screw) and let the door hang by the hinges.

Servo Motor Assembly See Pic 1

3. Remove the vacuum hose from the servo motor and unplug the electrical harness connectors.
4. Remove the two screws from the servo motor assembly mounting bracket and position the servo for access to the vacuum diverter valve.
5. Remove the retaining pushnut and vacuum connector clip, unplug the multiple vacuum connector from the vacuum diverter valve.
6. Remove the pushnut that retains the servo motor overtravel spring and arm link to the blend door crank arm. Remove the servo assembly from the vehicle.

INSTALLATION
1. Connect the servo motor overtravel spring and arm link to the blend door crank arm. Install a new pushnut.
2. Connect the multiple vacuum connector to the vacuum diverter valve and secure it with a vacuum connector and a new retaining pushnut.
3. Position the servo motor and install the two mounting screws.
4. Connect the vacuum hose to the servo motor and connect the electrical connector to the harness.
5. Replace the glove compartment door stop screw.
6. Connect the battery ground cable.

NOTE: On vehicles equipped with Electronic Engine Control (EEC), when the battery has been disconnected and reconnected, some abnormal drive symptoms may occur while the EEC processor relearns its adaptive strategy. The vehicle may need to be driven 10 miles or more to relearn the strategy.

7. Check the ATC system for proper operation.

__________________________________

I hope something here helps. Let me know if you have other questions.

Take care,
Joe

The first picture you show with the upper radiator hose going into that housing with 2 bolts on it, that is the thermostat housing, the thermostat is right under it!

For the heating problem, are both heater core hoses hot, *the hoses that go into the firewall from the engine*

if the uper and lower radiator hose isnt hot then I do not think it is a thermostat problem.

The hose going in and out to the core does one of them feel noticebly hotter or they both the same?

The top pic shows the thermostat, it's at the end of the hose at the block, the small hose with it is the bypass hose.
The bottom pic shows the heat control valve, m,ake sure the vacuum work to it, if this lever does not move, hot water will not enter the heater core! COLD air will result!

You can as a test remove the heat control valve and install a flush tee, this will eliminate the heat control valve! Buy the Prestone flush kit, the tee is in the kit...

What happens when you reach 85? If it keeps cooling down try the interior amient temp sensor. May just need the vacuum tube cleaned out. Its about an inch in diamiter and the sensor is that 3 oblong ed holre by the shifter in the dash. Take out and clean with compressed air. Or your blend door servo is loosing vaccum!

Feel the second hose if they are the same temp then the core is probably not restricted! The new core is about 50 bucks, on your model im not sure if the core is right behind the glovebox, I think it is because of the year. But it also may be under the dash.

But it sure sounds like it to me. Good luck