Toyota Car models Heater core Replacing Procedure?

The procedure mentioned here is similar for Toyota Celica, Corolla, ECHO & MR2 car models.

The details are provided below with diagrams and step by step instructions:---

The Toyota Heater core removal/ Installation Procedure:---

AUTION

NEVER open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

Fig. The heater core (radiator) is located inside the heater unit

1. Have the A/C system evacuated by a EPA-certified technician.
2. Remove the cooling unit.
3. Disconnect the suction tube and liquid tube from the cooling unit fitting. Cap all fittings immediately to keep moisture out of the system.
4. Remove the grommets and drain pipe grommet.
5. Remove the glove compartment assembly.
6. Disconnect the wiring from the cooling unit, unbolt and extract the unit.
7. Drain the engine coolant from the radiator.
8. Unbolt the heater control valve, label and disconnect the water hoses.
9. Remove the pipe grommets.
10. Remove the instrument panel and reinforcement.
11. Label and disconnect the heater unit wiring harnesses. Remove the retaining nuts around the heater unit and extract the assembly from the dash.
12. Unscrew the heater air duct and loosen the pipe clamps. Pull the heater core with return pipe out of the unit.
13. Install the components in the reverse order of removal securing all clamps and screws till snug.
14. Fill the cooling system, then start and warm the engine, making sure it stays full. Stop the engine and check for leaks and top off the system if necessary.
15. Have the A/C system charged by a certified automotive technician.
16. Check for proper heater operation.

1. Disconnect the negative battery cable.
2. Drain the cooling system into a clean container for reuse.
3. Discharge and recover the air conditioning system refrigerant.
4. Remove the evaporator housing by performing the following procedure:
   
   
   Disconnect the refrigerant lines from the evaporator core. Discard the O-rings. Plug the openings to prevent contamination.

   Remove the 2 grommets and the drain pipe grommet.

   At the passenger-s side, remove the lower finish panel.

   Disconnect the evaporator housing-s electrical connector.

   Remove the evaporator housing-to-chassis 3 nuts and 4 bolts.

   Remove the evaporator housing.
5. Remove the heater valve-to-cowl bolt.
6. Remove the heater hoses from the heater core pipes.
7. Remove the heater pipe grommets.
8. Remove the air bag module and the steering wheel by performing the following procedure:
   
   
   Place the front wheels in the straight-ahead position.

   At both sides of the steering wheel, remove the screw covers.

   Using a Torx socket, loosen the 2 air bag module-to-steering wheel Torx screws until the circumference ring catches on the screw case.

   Carefully, remove the air bag module and disconnect the electrical connector.

   Remove the steering wheel nut.

   Using a steering wheel puller, press the steering wheel from the steering column.
9. Remove the instrument panel and reinforcement by performing the following procedure:
   
   
   Remove the front pillar lower garnishes and the pillar garnishes.

   Remove the front door scuff plates.

   Remove the cowl side trim boards.

   Remove the steering column covers.

   Pry out the upper console panel by disengaging the 4 clips.

   Remove the console box.

   Remove the No. 1 finish panel.

   Remove the finish panel and the combination switch.

   Remove the lower cluster finish panel and the cluster finish panel.

   Remove the No. 1 register and the combination meter.

   Remove the 2 center cluster finish panel screws; then, pry out the finish panel.

   Remove the air conditioning control assembly.

   Remove the lower finish panel.

   Remove the glove compartment door finish plate located inside the lower finish panel.

   Pull up the air bag electrical connector and disconnect it.

   Remove the 5 lower finish panel screws and the panel.

   Remove the 4 bolts and lower pad inserts.

   Remove the 4 lower center finish panel screws and the panel.

   Remove the No. 2 side defroster nozzle.

   Disconnect the instrument panel electrical connectors.

   Remove the instrument panel 9 bolts and 2 nuts.

   Remove the instrument panel.

   Remove the No. 1 center console bracket bolt and 2 nuts.

   Remove the No. 2 center console bracket nut and bolt.

   Remove the brake spring.

   Remove the center console bracket support 6 bolts and 2 nuts.

   Remove the center console bracket.
10. Disconnect the connector and the electrical connector from the heater housing.
11. Remove the 4 heater housing-to-chassis nuts and heater housing.
12. Remove the 2 air outlet damper control servo motor screws and the servo motor.
13. Remove the air vent duct.
14. Remove the 2 heater air duct screws, the 2 clips and the duct.
15. Remove the 3 heater pipe clamp screws and the clamps.
16. Remove the heater core from the heater housing. 
    
    
    
    Fig. Exploded view of the air bag module, steering wheel and related components (typical)-Celica
17. 
    

Fig. Exploded view of the instrument panel and related components-Celica


Fig. Exploded view of the ventilation system, wiring harness and related components-Celica


Fig. Exploded view of the heater core, heater housing, evaporator housing and related components-Celica

To install:

1. Install the heater core to the heater housing.
2. Install the heater pipe clamp and the 3 clamp screws.
3. Install the heater air duct, the 2 clips and the 2 duct screws.
4. Install the air vent duct.
5. Install the air outlet damper control servo motor and the 2 servo motor screws.
6. Install the heater housing and 4 heater housing-to-chassis nuts.
7. Connect the connector and the electrical connector to the heater housing.
8. Install the air bag module and the steering wheel by performing the following procedure:
   
   
   Align the matchmarks and install the steering wheel to the steering column.

   Install the steering wheel nut and torque the nut to 26 ft. lbs. (35 Nm).

   Carefully, connect the electrical connector and install the air bag module.

   Using a Torx socket, tighten the 2 air bag module-to-steering wheel Torx screws to 78 inch lbs. (8.8 Nm).

   At both sides of the steering wheel, install the screw covers.
9. Install the instrument panel and reinforcement by performing the following procedure:
   
   
   Install the center console bracket.

   Install the center console bracket support 6 bolts and 2 nuts.

   Install the brake spring.

   Install the No. 2 center console bracket nut and bolt.

   Install the No. 1 center console bracket bolt and 2 nuts.

   Install the instrument panel.

   Install the instrument panel 9 bolts and 2 nuts.

   Connect the instrument panel electrical connectors.

   Install the No. 2 side defroster nozzle.

   Install the lower center finish panel and the 4 panel screws.

   Install the 4 bolts and lower pad inserts.

   Install the lower finish panel and the 5 panel screws.

   Connect the air bag electrical connector.

   Install the glove compartment door finish plate located inside the lower finish panel.

   Install the lower finish panel.

   Install the air conditioning control assembly.

   Install the center cluster finish panel and the 2 finish panel screws.

   Install the No. 1 register and the combination meter.

   Install the lower cluster finish panel and the cluster finish panel.

   Install the finish panel and the combination switch.

   Install the No. 1 finish panel.

   Install the console box.

   Pry out the upper console panel by engaging the 4 clips.

   Install the steering column covers.

   Install the cowl side trim boards.

   Install the front door scuff plates.

   Install the front pillar lower garnishes and the pillar garnishes.
10. Install the heater pipe grommets.
11. Install the heater hoses to the heater core pipes.
12. Install the heater valve-to-cowl bolt.
13. Install the evaporator housing by performing the following procedure:
    
    
    Install the evaporator housing.

    Install the evaporator housing-to-chassis 3 nuts and 4 bolts.

    Connect the evaporator housing-s electrical connector.

    At the passenger-s side, install the lower finish panel.

    Install the 2 grommets and the drain pipe grommet.

    Using new O-rings, connect the refrigerant lines to the evaporator core.
14. Refill the cooling system.
15. Connect the negative battery cable.
16. Evacuate, charge and leak test the air conditioning system.
17. Operate the engine to normal operating temperatures; then, check the climate control operation and check for leaks.

1. Disconnect the negative battery cable.
   
   CAUTION

   After Connecting the negative battery cable, wait for at least 1 ¹ / ₂ minutes for the SRS to deplete its energy.
2. Drain the cooling system into a clean container for reuse.
3. Disconnect the heater hoses from the heater core.
4. Discharge and recover the air conditioning system refrigerant.
5. Remove the air bag module and the steering wheel by performing the following procedure:
   
   
   Place the front wheels in the straight-ahead position.

   At both sides of the steering wheel, remove the screw covers.

   Using a Torx socket, loosen the 2 air bag module-to-steering wheel Torx screws until the circumference ring catches on the screw case.

   Carefully, remove the air bag module and disconnect the electrical connector.

   Remove the steering wheel nut.

   Using a steering wheel puller, press the steering wheel from the steering column.
6. Remove the passenger-s side air bag module by performing the following procedure:
   
   
   Remove the glove box-to-instrument panel 2 bolts and 3 screws; then, pull out the glove box and remove it.

   Disconnect the passenger-s side air bag module electrical connector.

   Remove the 2 passenger-s air bag module-to-instrument panel bolts and nuts. Carefully, remove the air bag module.
7. Remove the following items in the following order:
   
   
   The front door scuff plates

   The cowl side trims

   The front pillar garnishes

   Remove the 2 lower finish panel bolts and the panel.

   Disconnect the hood lock control cable.

   Remove the 2 lower insert bolts and the lower insert.

   Remove the 2 cluster finish panel screws; then, pry out the panel.

   Remove the steering column cover.

   Remove the steering column-s combination switch.

   Remove the No. 2 heater-to-register duct.

   Disconnect and remove the combination meter.

   Remove the steering column-to-instrument panel fasteners, the steering column shaft pinch bolt and the steering column.
8. Remove the following items in the following order:
   
   
   The lower left side panel

   The lower right side panel

   The shifting hole knob (manual transmission)

   The shifting hole bezel (automatic transmission)

   The rear console box

   Remove the center lower cluster finish panel by prying it out, disconnect the electrical connector and remove it.
9. Remove the following items in the following order:
   
   
   The stereo opening cover

   The lower center finish panel

   The air conditioning control panel

   Remove the center cluster finish panel by prying it out.

   Remove the radio.

   Disconnect the instrument panel electrical connectors.

   Remove the 4 instrument panel screws and the instrument panel.
10. Remove the following items in the following order:
    
    
    The heater-to-register duct

    The lower defroster nozzle

    The No. 1 and No. 2 braces

    The reinforcement
11. Remove the evaporator housing by performing the following procedure:
    
    
    Disconnect the cruise control actuator connector.

    Remove the 3 cruise control actuator set bolts.

    Using tool No. 09870-00025 (liquid line) and/or 09870-00015 (suction line), disconnect the refrigerant line clamps. Discard the O-rings and plug the openings to prevent contamination.

    Remove the tube grommet and the drain hose grommet.

    Disconnect the air conditioning amplifier electrical connector.

    Remove the 2 air conditioning amplifier nuts and the amplifier.

    Disconnect the evaporator housing-s electrical connectors.

    Remove the evaporator housing-to-chassis 3 screws, nut and the housing.
12. Pull back the carpet and remove the rear heater ducts.
13. Disconnect the wiring harness from the heater housing.
14. Remove the 3 heater housing-to-chassis nuts and the heater housing.
15. Remove the air duct-to-heater housing screw, the 5 clips and the duct.
16. Release the 2 heater core cover clips and the cover.
17. Remove the heater core-to-heater housing screw, clamp and the heater core.
    
    
    

    

    Fig. View of the heater/air conditioning assembly and related components-Corolla
    
    
    
    

    

    Fig. Exploded view of the instrument panel and related components-Corolla
    
    
    
    

    

    Fig. Exploded view of the ventilation system, wiring harness and related components-Corolla
    
    
    
    

    

    Fig. Using the special tool to remove the air conditioning refrigerant line clamps-Corolla
    
    
    
    

    

    Fig. Exploded view of the heater core, heater housing, evaporator housing and related components-Corolla

To install:

1. Install the heater core, clamp and the heater core-to-heater housing screw.
2. Install the heater core cover and the 2 cover clips.
3. Install the air duct, the 5 clips and the duct-to-heater housing screw.
4. Install the heater housing and the 3 heater housing-to-chassis nuts.
5. Connect the wiring harness to the heater housing.
6. Install the rear heater ducts and the carpet.
7. Install the evaporator housing by performing the following procedure:
   
   
   Install the evaporator housing-to-chassis 3 screws, nut and the housing.

   Connect the evaporator housing-s electrical connectors.

   Install the 2 air conditioning amplifier nuts and the amplifier.

   Connect the air conditioning amplifier electrical connector.

   Install the tube grommet and the drain hose grommet.

   Using new O-rings, connect the refrigerant line clamps.

   Install the 3 cruise control actuator set bolts.

   Connect the cruise control actuator connector.
8. Install the following items in the following order:
   
   
   The reinforcement

   The No. 1 and No. 2 braces

   The lower defroster nozzle

   The heater-to-register duct

   Install the instrument panel and the 4 instrument panel screws.

   Connect the instrument panel electrical connectors.

   Install the radio.

   Install the center cluster finish panel.
9. Install the following items in the following order:
   
   
   The air conditioning control panel

   The lower center finish panel

   The stereo opening cover

   Connect the electrical connector and install the center lower cluster finish panel.
10. Install the following items in the following order:
    
    
    The rear console box

    The shifting hole bezel (automatic transmission)

    The shifting hole knob (manual transmission)

    The lower right side panel

    The lower left side panel

    Install the steering column, the steering column shaft pinch bolt and the steering column-to-instrument panel fasteners.

    Connect and install the combination meter.

    Install the No. 2 heater-to-register duct.

    Install the steering column-s combination switch.

    Install the steering column cover.

    Install the cluster finish panel and the 2 panel screws.

    Install the lower insert and the 2 lower insert bolts.

    Connect the hood lock control cable.

    Install the lower finish panel and the 2 panel bolts.
11. Install the following items in the following order:
    
    
    The front pillar garnishes

    The cowl side trims

    The front door scuff plates
12. Install the passenger-s side air bag module by performing the following procedure:
    
    
    Carefully, Install the air bag module and the 2 passenger-s air bag module-to-instrument panel bolts and nuts.

    Connect the passenger-s side air bag module electrical connector.

    Install the glove box and the glove box-to-instrument panel 2 bolts and 3 screws.
13. Install the air bag module and the steering wheel by performing the following procedure:
    
    
    Align the matchmarks and install the steering wheel to the steering column.

    Install the steering wheel nut and torque the nut to 26 ft. lbs. (35 Nm).

    Carefully, connect the electrical connector and install the air bag module.

    Using a Torx socket, tighten the 2 air bag module-to-steering wheel Torx screws to 78 inch lbs. (8.8 Nm).

    At both sides of the steering wheel, install the screw covers.
14. Connect the heater hoses to the heater core.
15. Refill the cooling system.
16. Connect the negative battery cable.
17. Evacuate, charge and leak test the air conditioning system refrigerant.

Fig. Instrument panel removal exploded view-MR2

Fig. Evaporator case removal-MR2

Fig. Instrument panel cross brace removal-MR2

Fig. Heater unit removal-MR2

Fig. Heater core removal-MR2

1. Before servicing the vehicle, refer to the Precautions section.
2. Drain the cooling system.
3. Discharge the A/C system.
4. Remove or disconnect the following:
   
   
   Negative battery cable

   Luggage compartment trim box cover

   Heater hoses

   Pipe grommets

   Steering wheel

   Door scuff plates

   Cowl side trims

   No. 1 lower finish panel

   Instrument panel lower pad insert

   Steering column covers

   Spiral cable

   Wiper/washer switch

   Light control /headlight dimmer switch

   Instrument cluster finish panel

   Combination meter

   Glove compartment door

   Passenger airbag assembly

   Passenger airbag manual switch

   Hood release lever

   Center instrument cluster finish panel

   Ash tray outer case

   Stereo finish panel

   Instrument panel brace inner and outer covers

   Heater control cables

   Heater control assembly

   Steering column

   Front pillar garnishes

   Instrument panel lower mount bracket

   Center instrument panel bracket

   Instrument panel braces

   Instrument panel

   Instrument panel reinforcement

   A/C system suction tube and liquid line

   Blower resistor connector

   Thermistor connector

   Cooling unit

   Heater unit

   Heater core

To install:

1. Install or connect the following:
   
   
   Heater core

   Heater unit

   Cooling unit

   Thermistor connector

   Blower resistor connector

   A/C system suction tube and liquid line

   Instrument panel reinforcement

   Instrument panel

   Instrument panel braces

   Center instrument panel bracket

   Instrument panel lower mount bracket

   Front pillar garnishes

   Steering column

   Heater control assembly

   Heater control cables

   Instrument panel brace inner and outer covers

   Stereo finish panel

   Ash tray outer case

   Center instrument cluster finish panel

   Hood release lever

   Passenger airbag manual switch

   Passenger airbag assembly

   Glove compartment door

   Combination meter

   Instrument cluster finish panel

   Light control /headlight dimmer switch

   Wiper/washer switch

   Spiral cable

   Steering column covers

   Instrument panel lower pad insert

   No. 1 lower finish panel

   Cowl side trims

   Door scuff plates

   Steering wheel

   Pipe grommets

   Heater hoses

   Luggage compartment trim box cover

   Negative battery cable
2. Fill the cooling system.
3. Recharge the A/C system.
4. Start the engine and check for leaks.

These details will help.

Thanks.

FOR MORE HELP GO TO: ---

Car repair guide?

http://technoanswers.blogspot.in/2012/03/car-repair-guide.html