REMOVAL & INSTALLATION
Removing the heater core requires removal of the dashboard and the air conditioner evaporator. Removal of the air conditioner evaporator requires the A/C system to be discharged. The legal ramifications of discharging A/C systems without the proper EPA certification, experience, and equipment dictate that the A/C components on your vehicle should be serviced only by a Motor Vehicle Air Conditioning (MVAC) trained, and EPA certified automotive technician using approved equipment.
If you insist upon servicing the heater core and you are not a Motor Vehicle Air Conditioning (MVAC) trained, and EPA certified automotive technician and/or you do have the approved equipment for discharging and recovery of the A/C refrigerant, before disabling your vehicle, take your vehicle to an approved repair facility and have the A/C system discharged prior to beginning the heater core repair procedure.
- Take your vehicle to an approved repair facility and have the A/C system discharged.
- Turn the ignition to the ON position and set the heater temperature knob to the full heat position, then turn the ignition switch to the OFF position.
- Disconnect the negative battery cable.
- From under the hood, locate the heater control valve on the lower passenger's side firewall area just below the fuel filter. Disconnect the clamp securing the heater valve cable to the heater valve and remove the cable.
- Make sure the heater valve is in the full hot position by pressing the arm toward the firewall.
- Allow the engine to cool if the coolant temperature is above 100°F (37°C).
- Drain the engine coolant from the radiator into a suitable and sealable container.
- On 4-cylinder Odyssey models, remove the upper intake manifold.
- Place a drain pan below the two heater hoses at the firewall, release the tension on both heater hose clamps and slide the clamps up the heater hose away from the firewall and remove the two hoses.
- Drain the coolant from the hoses into the drain pan and then into a suitable and sealable container.
- Remove the nut attached to the stud protruding through the firewall, just above and to the right of the heater hoses.
- Remove the dashboard assembly. Refer to Body for specific details.
- On 4-cylinder Odyssey models, remove the steering hanger beam, center dash supports and the upper cover plate.
Remove the evaporator as follows:
- Note the entertainment system security code, then disconnect the negative battery cable, then the positive cable and remove the battery.
- From under the hood, unbolt and remove the suction and receiver lines from the evaporator. Plug of cap the lines and the receiver immediately to avoid moisture and debris contamination.
- Remove the glove box assembly.
- Remove the passenger dashboard lower cover, then remove the glove box frame and knee bolster bracket.
- Disconnect the evaporator temperature sensor and wire harness.
- Remove the evaporator mounting screws, mounting bolt and mounting nut, disconnect the drain hose and remove the evaporator assembly.
- Detach the electrical connectors from the heater mode control motor and air mix control motor, then remove the wire harness clips and wire harness from the heater unit.
- Remove the clip from the heater duct, and remove the heater unit mounting nuts and remove the heater unit.
Take care not to tip the heater unit as residual coolant may spill.
- Remove the heater core cover.
- Remove the heater core pipe grommet.
- Remove the heater core pipe clamp.
- Carefully remove the heater core assembly.
The installation procedure is in reverse order of disassembly making note of the following points.
For the air conditioning system:
Replace any removed A/C O-rings and coat them with a light coating of refrigerant oil before installing them.
For the heater system:
Apply a suitable sealant to the grommets.