1993 Mercury Marquis HEATER CORE

Tiny
SIXELP3
  • MEMBER
  • 1993 MERCURY MARQUIS
  • V8
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
HOW DO TAKE OUT THE HEATER?
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Thursday, October 1st, 2009 AT 3:25 PM

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Tiny
BLUELIGHTNIN6
  • EXPERT
REMOVAL:

Disconnect the negative battery cable.
Drain the cooling system and disconnect the heater hoses from the heater core tubes. Plug the hoses and the heater core tubes to prevent coolant leakage.
Remove the 3 nuts located below the windshield wiper motor attaching the left end of the plenum to the dash panel. Remove the 1 nut retaining the upper left corner of the evaporator case to the dash panel.
Disconnect the vacuum supply hose(s) from the vacuum source. Push the grommet and vacuum supply hose(s) into the passenger compartment.
Remove the right and left lower instrument panel insulators.
Remove the 2 screws attaching the pad to the instrument panel at each defroster opening. Be careful not to drop the screws into the defroster openings.
Remove the one screw attaching each outboard end of the pad to the instrument panel.
Remove the 5 screws attaching the lower edge of the pad to the instrument panel. Pull the instrument panel pad rearward and remove it from the vehicle.
Remove all instrument panel mounting screws and pull the instrument panel back as far as it will go without disconnecting any wiring harnesses.
Make sure the nuts attaching the instrument panel braces to the dash panel are removed.
Loosen the right door sill plate and remove the right side cowl trim panel.
If equipped with manual air conditioning, disengage the temperature control cable housing from the bracket on top of the plenum. Disconnect the cable from the temperature blend door crank arm.

If equipped with Automatic Temperature Control (ATC), proceed as follows:
A. On 1989 vehicles, disconnect the temperature control cable from the ATC sensor.
B. Detach the vacuum harness line connector from the ATC sensor harness and detach the electrical connector from the ATC servo connector.
C. On 1990-98 vehicles, remove the cross body brace and disconnect the wiring harness from the temperature blend door actuator. Detach the ATC sensor tube from the evaporator case connector.

Detach the vacuum jumper harness at the multiple vacuum connector near the floor air distribution duct.
Disconnect the white vacuum hose from the outside-recirculating door vacuum motor.
Remove the 2 hush panels.
Remove 1 plastic push fastener retaining the floor air distribution duct to the left end of the plenum.
Remove the left screw and loosen the right screw on the rear face of the plenum and remove the floor air distribution duct.
Remove the 2 nuts from the 2 studs along the lower flange of the plenum.
Carefully move the plenum rearward to allow the heater core tubes and the stud at the top of the plenum to clear the holes in the dash panel. Remove the plenum from the vehicle by rotating the top of the plenum forward, down and out from under the instrument panel. Carefully pull the lower edge of the instrument panel rearward, as necessary, while rolling the plenum from behind the instrument panel.
Remove the 4 retaining screws from the heater core cover and remove the cover from the plenum assembly.
Pull the heater core and seal assembly from the plenum assembly.

INSTALLATION:

Carefully install the heater core and seal assembly into the plenum assembly. Visually check to ensure that the core seal is properly positioned. Position the heater core cover and install the 4 retaining screws.
On 1989 vehicles with ATC, install the ATC servo on the plenum.
Route the vacuum supply hose through the dash panel and seat the grommet in the opening.
Position the plenum under the instrument panel with the register duct opening up and the heater core tubes down. Rotate the plenum up behind the instrument panel and position the plenum to the dash panel. Insert the heater core tubes and mounting studs through their respective holes in the dash panel and the evaporator case.
Install the 3 nuts on the studs along the lower flange and one on the upper flange of the plenum. Install the 3 nuts below the windshield wiper motor to attach the left end of the plenum to the dash panel and the one nut to retain the upper left corner of the evaporator case to the dash panel.
Position the floor air distribution duct on the plenum. Install the 2 screws and plastic push fastener. If removed, position the panel door vacuum motor to the mounting bracket and install the 2 attaching screws.
Connect the white vacuum hose to the outside-recirculating door vacuum motor. Attach the vacuum jumper harness to the plenum harness at the multiple vacuum connector near the floor air distribution duct. Install the floor duct.
If equipped with manual air conditioning, connect the temperature control cable housing to the bracket on top of the plenum and connect the temperature control cable to the temperature blend door crank arm. Adjust the temperature cable.

If equipped with ATC, proceed as follows:
A. On 1989 vehicles, connect the temperature control cable to the ATC sensor and adjust the cable. Route and attach the vacuum harness connector to the ATC sensor and attach the electrical connector to the ATC servo connector. Do not block the sensor aspirator exhaust port with the excess vacuum harness. Install the ATC sensor tube between the sensor and the evaporator connector.
B. On 1990-98 vehicles, attach the ATC sensor tube to the evaporator case connector. Install the cross body brace and connect the wiring harness to the blend door actuator.

Install the bolt to attach the lower right end of the instrument panel to the side cowl. Install the right side cowl trim panel and tighten the right door sill plate attaching screws.
On 1990-98 vehicles, push the instrument panel back into position and install all instrument panel mounting screws. Install the right and left lower instrument panel insulators.
Connect the vacuum supply hose(s) to the vacuum source.
Install the right and left lower instrument panel insulators and install the 2 hush panels.
Unplug the heater core tubes and the heater hoses and connect the heater hoses to the heater core tubes. Fill the cooling system.
Connect the negative battery cable and check the system for proper operation.
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Thursday, October 1st, 2009 AT 8:05 PM

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