How to replace Heater Core on Cadillac CTS & DTS car models?

In this chapter the details to replace Heater core and heater hose is provided.The step by step procedure to remove Cadillac heater core and diagrams to replace heater core is provided.
The details to remove heater core from HVAC assembly.

The heater core replacing procedure is as follows:----

1. Disable the SIR system.
2. Disconnect the negative battery cable.
3. Drain the cooling system.
4. Remove the heater hose quick connects from the heater core pipes by performing the following procedure:
   1. At the passenger side, raise the air inlet screen and open the access door near the pollen filter.
   2. Unlock the quick connect collars by squeezing the tabs and carefully pulling back on the tabs to disconnect the sleeve.
   3. If green assembly marks are attached, discard them. 
      
      WARNING

      The front wheels must be maintained in the straight-ahead position and the steering column must be in the LOCK position. Failure to do so will cause improper alignment of some components during installation and may result to damage to the SIR coil assembly.
      
      
      
      
      Fig. View of a heater hose connector-CTS
5. Remove the steering column by removing or disconnecting the following:
   
   WARNING

   Handle the steering column with care for it is very susceptible to damage. Dropping, leaning or hammering on it could cause damage to its collapsible design.
   
   
   
   
   Instrument panel driver knee bolster energy absorber and sound insulator

   Steering column electrical connector(s)

   Coupler bolt from the lower steering column connection and slightly separate the coupler to aid in the shaft removal

   Using a chisel and a hammer, rotate the forward support strap shear nut and bolt (located under the steering column) counterclockwise in order to remove them

   Steering column-to-rear support bracket bolt

   Pull the steering column straight back and through the dash panel and remove it from the vehicle.
   
   
   
   
   

   

   Fig. View of the steering column assembly-CTS
6. Remove the instrument panel carrier by removing or disconnecting the following:
   
   NOTE

   It is not necessary to physically remove the instrument panel but it is necessary to pull the carrier rearward to enable the heater core to be removed from its housing.
   
   
   
   
   Windshield pillar moldings

   Access panel, the air deflector outlet screw, the air deflector outlet and the air outlet duct, located at the right-side of the instrument panel

   Instrument panel SIR (air bag) module cover, the instrument panel compartment and the SIR module

   Upper center console and the lower center console

   Center console air duct screw and the center console air duct

   Radio tape player bezel and the radio

   Climate control head

   Center air outlet deflector, the outlet screws and the outlet housing

   Driver-s side access panel

   Driver-s side air outlet deflector, the outlet screw and the outlet housing

   Driver-s side lower outlet duct

   Instrument cluster

   Fuse and relay panel screws and the panels

   Instrument panel carrier bolts

   Electrical connectors from the instrument panel and/or the wiring harness clips from the instrument panel carrier, if necessary

   Instrument panel carrier
   
   

   

   

   Fig. View of the instrument panel carrier bolt locations-CTS
   
   
   
   
   Blower motor housing screws and the housing with the motor

   Heater core pipe bracket-to-chassis screw and the bracket

   Heater core inlet/outlet pipe bracket-to-heater core screw and the inlet/outlet pipe bracket

   Instrument panel support brace bolts from the instrument panel and the transmission well, then remove the brace

   Heater core-to-housing retaining screw. Plug the heater core pipes and protect the interior from coolant spills

   Heater core and the rubber seal from the heater housing
   
   

   

   

   Fig. View of a heater core and seal-CTS

To install:

1. Install or connect the following:
   
   
   Rubber seal and heater core into the heater housing; be careful not to damage the fins

   Heater core-to-housing retainer screw

   Instrument panel support brace to the transmission well and instrument panel, then torque the bolts to 16 ft. lbs. (22 Nm)

   Heater core inlet/outlet pipe bracket to the heater core (using a new O-ring lightly coated with coolant), and torque the screw to 44 inch lbs. (5 Nm)

   Heater core pipe bracket with the screw to the chassis, be careful not to strip the screw

   Blower motor/housing assembly and torque the screws to 35 inch lbs. (4 Nm)

   Instrument panel carrier

   Instrument panel carrier by reversing the removal procedures and torque the instrument panel carrier bolts to 16 ft. lbs. (22 Nm)
2. Remove the steering column by installing or connecting the following:
   
   
   Steering column into the vehicle, through the dash panel and into the lower steering coupling

   Hand start the rear support bracket bolt, the forward support strap nut and shear bolt

   Rear support bracket bolt. Torque to 16 ft. lbs. (22 Nm)

   Forward support strap nut. Torque to 16 ft. lbs. (22 Nm)

   New forward support shear bolt. Torque to 15 ft. lbs. (21 Nm)

   Lower steering column shaft bolt and torque to 16 ft. lbs. (22 Nm)

   Steering column electrical connector(s)

   Sound insulator and the instrument panel driver knee bolster energy absorber
3. Connect the heater hoses to the heater core pipes by performing the following procedure:
   1. If not attached to the quick connect, discard the green assembly marker(s).
   2. Push the quick connects into the pipes until they are fully seated.
   3. Squeeze the locking tabs and press the retaining sleeve into the locked position.
   4. At the passenger side, close the access door near the pollen filter and lower the air inlet screen.
4. Refill the cooling system by performing the following procedure:
   1. Add a 50/50 mixture of water and DEX-COOL® antifreeze to the KALT/COLD mark (seam) on the surge tank.
   2. Start the engine and allow it to idle for 1 min.
   3. Add more coolant to the surge tank as necessary.
   4. Install the radiator sure tank cap.
   5. Cycle the engine, from idle to 3000 rpm, in 30 second intervals, until the engine reaches normal operating temperatures.
      
      NOTE

      The cooling system will bleed itself automatically during warm-up.
   6. Turn the engine OFF and recheck the coolant level when the engine is cool
5. Connect the negative battery cable.
6. Enable the SIR system.
7. Reprogram the necessary accessories.

1. Before servicing the vehicle, refer to the Precautions Section.
2. Disable the SIR system.
3. Disconnect the negative battery cable.
4. Drain the cooling system.
5. Recover the refrigerant.
6. Remove the evaporator tube from the thermal expansion valve.
7. Remove the heater hoses from the heater core.
   
   
   

   

   Fig. View of heater hoses and connections
8. Remove the driver knee bolster.
9. Remove the brake pedal bracket assembly as follows:
   1. Disconnect the electrical connector for the brake pedal position sensor.
   2. Accelerator pedal assembly nuts.
   3. Accelerator pedal assembly.
   4. Brake pedal push rod retainer clip.
   5. Brake pedal assembly nuts.
10. Pull back and reposition the carpet.
11. Remove the lower Instrument Panel (I/P) support brace.
12. Reposition the auxiliary air distribution duct.
13. Remove the instrument panel top pad.
    
    
    

    

    Fig. Instrument panel top pad removal view
14. Remove the instrument panel center trim panel.
15. Remove the left instrument panel accessory trim plate.
16. Remove the instrument the panel cluster assembly.
    
    WARNING

    The front wheels must be maintained in the straight-ahead position and the steering column must be in the LOCK position. Failure to do so will cause improper alignment of some components during installation and may result to damage to the SIR coil assembly.
17. Disconnect the intermediate steering shaft from the steering gear.
18. Remove the steering column mounting nuts.
19. Disconnect any electrical connectors as needed.
20. If equipped with AN3. disconnect the automatic transmission range selector cable.
21. Remove the steering column.
    
    
    

    

    Fig. Steering column and mounting nuts shown
22. Remove glove box.
23. Remove the instrument panel ashtray assembly, if equipped.
24. Remove the center console, if equipped.
25. Remove the radio.
26. Remove the HVAC control Assembly. Refer to HVAC Control Assembly Replacement.
27. Remove the instrument panel left air outlet.
28. Remove the right and left side window air outlet ducts.
29. Remove the instrument panel right air outlet.
30. Remove the instrument panel lower panel bolts.
31. Disconnect the electrical harness connections.
32. Remove the instrument lower panel.
    
    
    

    

    Fig. Instrument lower panel and mounting bolts shown
33. Remove the left and right air distribution duct.
34. Remove the center air outlet duct.
35. Remove the floor air outlet duct.
36. Remove the left and right side window defroster outlet duct.
37. Remove the screws securing the windshield defroster nozzle duct to the carrier.
38. Remove the instrument panel carrier assembly nuts.
39. Remove the instrument panel carrier assembly bolts.
40. With the aid of an assistant, remove the instrument panel carrier assembly.
    
    
    

    

    Fig. Instrument panel carrier assembly and mounting hardware
41. Disconnect the HVAC module assembly electrical connectors.
42. Remove the HVAC module assembly mounting nuts.
43. Remove the left hand floor duct.
44. With the aid of an assistant, remove the HVAC module assembly and place on work bench.
45. Remove the TXV pass through seal.
46. Remove the heater and A/C pipe cover screws.
47. Remove the heater and A/C pipe cover.
48. Remove the heater core tube clamp screw.
49. Remove the heater core tube clamp
50. Remove the heater core.
    
    
    

    

    Fig. Heater core removal from HVAC module assembly

To install:

1. Install heater core.
2. Install the heater core tube clamp and screw, tighten the screw to 9 inch lbs. (1 Nm).
3. Install the heater and A/C pipe cover and screws, tighten the screws to 9 inch lbs. (1 Nm).
4. Install the TXV pass through seal.
5. With the aid of an assistant, carefully install the HVAC assembly into the vehicle.
6. Install the left hand floor duct.
7. Install the HVAC module assembly mounting nuts. Tighten the mounting nuts to 80 inch lbs. (9 Nm).
8. Reconnect the HVAC module assembly electrical connectors.
9. With the aid of an assistant, install the instrument panel carrier assembly.
10. Install the instrument panel carrier assembly nuts and bolts. Tighten the nuts and bolts to 18 ft. lbs. (25 Nm).
11. Install the screws securing the windshield defroster nozzle duct to the carrier. Tighten the screws to 9 inch lbs. (1 Nm).
12. Install the left and right side window defroster outlet duct. Tighten the screws to 14 inch lbs. (1.5 Nm).
13. Install the floor air outlet duct, tighten the screws to 14 inch lbs. (1.5 Nm).
14. Install the center air outlet duct, tighten the screws to 9 inch lbs. (1 Nm).
15. Install the left and right air distribution duct, tighten the screws to 9 inch lbs. (1 Nm).
16. With the aid of an assistant, install the instrument panel lower panel.
17. Install the instrument panel lower panel bolts. Tighten the bolts to 80 inch lbs. (9 Nm).
18. Install the instrument panel right air outlet.
19. Install the right and left side window air outlet ducts.
20. Install the HVAC control Assembly.
21. Install the radio.
22. Install the center console, if equipped.
23. Install the instrument panel ashtray assembly, if equipped.
24. Install the glove box. Tighten the mounting screws to 18 inch lbs. (2 Nm).
25. Install the steering column.
26. If equipped with AN3. reconnect the automatic transmission range selector cable.
27. Install any electrical connectors as needed.
28. Reconnect the intermediate steering shaft to the steering gear.
29. Install the steering column mounting bolts. Tighten the nuts to 18 ft. lbs. (25 Nm).
30. Install the instrument panel cluster assembly. Tighten screws to 18 inch lbs. (2 Nm).
31. Install the left instrument panel accessory trim plate. Snap into place.
32. Install the instrument panel top pad. Tighten the bolts to 80 inch lbs. (9 Nm).
33. Reposition the auxiliary air distribution duct.
34. Install the lower Instrument Panel (I/P) support brace. Tighten the bolts to 18 ft. lbs. (25 Nm).
35. Reposition the carpet.
36. Install the brake pedal bracket assembly as follows:
    1. Reconnect the electrical connector for the brake pedal position sensor.
    2. Accelerator pedal assembly nuts.
    3. Accelerator pedal assembly.
    4. Brake pedal push rod retainer clip.
    5. Brake pedal assembly nuts.
37. Install the driver knee bolster. Tighten the mounting screws to 18 inch lbs. (2 Nm).
38. Install the heater hoses to the heater core.
39. Install the evaporator tube to the thermal expansion valve.
40. Evacuate and recharge A/C system.
41. Leak test the fitting of the reinstalled component using a halogen leak detector.
42. Refill cooling system and the bleed system as follows:
    1. Add a 50/50 mixture of water and DEX-COOL® antifreeze to the KALT/COLD mark (seam) on the surge tank.
    2. Start the engine and allow it to idle for 1 min.
    3. Add more coolant to the surge tank as necessary.
    4. Install the radiator sure tank cap.
    5. Cycle the engine, from idle to 3000 rpm, in 30 second intervals, until the engine reaches normal operating temperatures.
    6. Turn the engine OFF and recheck the coolant level when the engine is cool.
43. Connect the negative battery cable.
44. Enable the SIR system.
45. Reprogram the necessary accessories.

These details will help.

Thanks.

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