Heater Unit/Core Replacement

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Honda Odyssey, 2003 Honda Odyssey, 2002 Honda Odyssey, 2001 Honda Odyssey, and 2000 Honda Odyssey. However, it is still accessible from the selected car via links, so may be relevant.

SRS components are located in this area. Review the SRS component locations, and the precautions and procedures (see AIR BAG RESTRAINT SYSTEMS ) before performing repairs or service.

Make sure you have the anti-theft code for the radio and the navigation system, then write down the frequencies for the radio's preset buttons.
Disconnect the negative cable from the battery.
From under the hood, open the cable clamp (A), then disconnect the heater valve cable (B) from the heater valve arm (C). Turn the heater valve arm to the fully opened position as shown.

Fig 1: Opening Cable Clamp
Courtesy of AMERICAN HONDA MOTOR CO., INC.
When the engine is cool, drain the engine coolant from the radiator (see COOLANT REPLACEMENT ).
Slide the hose clamps (A) back, then disconnect the inlet heater hose (B) and the outlet heater hose (C) from the heater unit. Engine coolant will run out when the hoses are disconnected; drain it into a clean drip pan. Be sure not to let coolant spill on the electrical parts or the painted surfaces. If any coolant spills, rinse it off immediately.

Fig 2: Sliding Hose Clamps
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Remove the mounting nut from the heater unit. Take care not to damage or bend the fuel lines and the brake lines, etc.

Fig 3: Removing Mounting Nut From Heater Unit
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Remove the dashboard (see DASHBOARD LOWER COVER REMOVAL/INSTALLATION ).
Remove the evaporator (see Evaporator Removal and Installation ).
Remove the mounting bolts and the heater unit.

Fig 4: Removing Mounting Bolts & Heater Unit
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Remove the self-tapping screws and the clamp (A), then carefully pull out the heater core (B) so you don't bend the inlet and outlet pipes.

Fig 5: Removing Self-Tapping Screws & Clamp
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Install the heater core in the reverse order of removal.
Install the heater unit in the reverse order of removal and note these items:
- Do not interchange the inlet and outlet heater hoses, and install the hose clamps securely.
- Refill the cooling system with engine coolant (see COOLANT REPLACEMENT ).
- Adjust the heater valve cable (see Heater Valve Cable Adjustment ).
- Make sure that there is no coolant leakage.
- Make sure that there is no air leakage.
- For evaporator and A/C-related information, refer to evaporator remove and installation (see Evaporator Removal and Installation ).
- Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
- Do the power window control unit resetting procedure (see RESETTING THE POWER WINDOW CONTROL UNIT '03-04 ).
- Enter the anti-theft code for the radio and the navigation system, then enter the customer's radio station presets.