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Mike S., Chevy Mechanic
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Experience:  ASE Certified Master Technician
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How do I remove the heater core on a 2003, 3500 chevy truck.

Customer Question

How do I remove the heater core on a 2003, 3500 chevy truck.
Submitted: 4 years ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 4 years ago.

hi

this should help you

thanks

please ACCEPT my answer so I can get credit for my work.i don't receive commission unless you do ..i'm not always going to be giving you good news,so please dont let this stand in the way of you accepting my answer.it does not cost you more money.we will still be able to communicate.. Bonuses and positive feedback are appreciated!if you are not satisfied with my answer,please do not leave bad feed back,i will gladly opt out and let another expert handle the question.PLEASE ASK IF YOU NEED MORE HELP

Service and Repair

HEATER/VENT MODULE REPLACEMENT

REMOVAL PROCEDURE



 

  1. Drain the engine coolant.
  2. If equipped remove the auxiliary battery.
  3. Disconnect the heater hoses.
  4. Remove the accumulator.
  5. Remove the instrument panel carrier.
  6. Remove the HVAC module drain hose.
  7. Disconnect the electrical harnesses and the ground connections as needed.

 



 

  1. Remove the mounting nuts and the screws from the HVAC module.
  2. Remove the HVAC module assembly from the vehicle.

INSTALLATION PROCEDURE



 

  1. If you are replacing the HVAC module, transfer the components from the old HVAC module as necessary.
  2. Install the HVAC module assembly to the vehicle. Precautions.
  3. Install the mounting nuts and the screws to the HVAC module.
Tighten
  • Tighten the mounting screws to 4 N.m (35 lb in) .
  • Tighten the mounting nuts to 9 N.m (80 lb in) .

 



 

  1. Connect the electrical harnesses and the ground connections.
  2. Install the HVAC module drain hose.
  3. Install the instrument panel carrier.
  4. Install the accumulator.
  5. Connect the heater hoses.
  6. Install the auxiliary battery.
  7. Fill the cooling system. Refer to Draining and Filling Cooling System.
Service and Repair

REMOVAL PROCEDURE


 

  1. Drain the engine coolant.
  2. Recover the refrigerant.
  3. Remove the heater/vent module. See: Housing Assembly HVAC\Service and Repair
  4. Remove the heater core cover screws.
  5. Remove the heater core cover.

 


 

  1. Remove the heater core.

INSTALLATION PROCEDURE


 

  1. Install the heater core.

 


 

  1. Install the heater core cover.
  2. Install heater core cover screws.
Tighten
Tighten the screws to 1.6 Nm (14 lb in) .
  1. Install the heater/vent module.
  2. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging.
  3. Refill the engine coolant. Refer to Draining and Filling Cooling System in Cooling System
Customer: replied 4 years ago.
I don't see any screws, don't know how to disassemble, the pictures don't show very much detail.
Expert:  Tim's Auto Repair replied 4 years ago.

ok

this is all i have on this one..i will opt out,mabe one of the other guys has a better instruction sheet

thanks

Customer: replied 4 years ago.
Can anyone answer, this is my first time on this site I don't know what to do next.
Customer: replied 4 years ago.
What do you need to know?
Customer: replied 4 years ago.
Thank you, XXXXX XXXXX you sent are much larger and show more detail, I know that Tim was very helpful but the schematics came through unclear. If you can clarify does the dash pad and instrument panal with radio have to be removed first? Do the plastic vents in the rear of the cab go directly to the heater box? If so is their a screen or barrier to prevent the free access to my cab?
Expert:  Mike S. replied 4 years ago.

2003 Chevrolet Silverado 3500

Heating, Ventilation, & Air Conditioning > Auxiliary Heating & Air Conditioning > Heater Core > Removal & Installation

Removal & Installation

  1. Drain the engine coolant.

  2. Remove the right rear quarter trim panel.

  3. Remove the right rear wheelhouse.

  4. Disconnect the auxiliary heater hoses from the heater core.

  5. Disconnect the electrical connectors, as necessary.

  6. Remove the drain valve (3).

  7. Remove the bolts (1)

  8. Remove the nuts (2, 4).

  9. Remove the heater module.

  10. Remove the blower motor, if necessary.

  11. Remove the heater case cover.

  12. Remove the heater core.

    Auxiliary heater core housing

    Auxiliary heater core housing

To install:

  1. Install the heater core.

  2. Install the heater case cover.

  3. Install the blower motor, if necessary.

  4. Install the heater module.

  5. Install the nuts (2, 4).

  6. Install the bolts.

  7. Tighten the following fasteners:

    • Tighten the bolts to 13 inch lbs. (1.5 Nm)

    • Tighten the nuts to 89 inch lbs. (10 Nm).

  8. Install the drain valve (3).

  9. Connect the electrical connectors, as necessary.

  10. Install the right rear wheelhouse.

  11. Install the right rear quarter trim panel.

  12. Add the engine coolant.

  13. Inspect the system for leaks. If the fluid charging system is not used, the system must be burped to release air bubbles.

Heating, Ventilation, & Air Conditioning > Heater Core > Removal & Installation

  1. Drain the engine cooling system into a clean container for reuse.

  2. Remove or disconnect the following:

    • Negative battery cable

    • Heater hoses from the heater core

    • Temperature control cable from the heater case assembly

    • Disconnect the mode control cable from the heater case assembly

    • Instrument panel carrier to provide access to the heater case assembly

    • Electrical connectors that may interfere with the heater case assembly removal

    • Heater case assembly-to-chassis screws/nuts and the assembly. Place the heater case assembly on a bench.

    • Heater core cover screws

    • Heater core from the heater case

      View of the heater case assembly-Sierra & Silverado

      View of the heater case assembly-Sierra & Silverado

      Click to Enlarge
      View of the heater core-Sierra & Silverado

      View of the heater core-Sierra & Silverado

      Click to Enlarge

To install:

  1. Install or connect the following:

    • Heater core to the heater case

    • Heater core cover screws and tighten to 14 inch lbs. (1.6 Nm)

    • Heater case assembly and the assembly-to-chassis screws, then, tighten the screws to 35 inch lbs. (4 Nm) and the nuts to 80 inch lbs. (9 Nm)

    • Electrical connectors, as necessary

    • Instrument panel carrier

    • Mode control cable to the heater case assembly

    • Temperature control cable to the heater case assembly

    • Heater hoses to the heater core

    • Negative battery cable.

  2. Refill the engine cooking system.

  3. Run the engine to normal operating temperatures; then, check the climate control operation and check for leaks.

 

Expert:  Mike S. replied 4 years ago.
It appears you have 2 heater cores. When you asked about the rear cab plastic vents I assume they are to the Auxiliary heater core housing. To clarify, which heater core are you taking out? www.compnine.com has those pictures.
Customer: replied 4 years ago.
I have no defrost and limited air flow from bottom vent in front, and a very strong mice urine smell on defrost especially. Since cab has no rust or rot and all rubber stops and seals are intact, I suspect that the mice are coming in from the two plastic vents at the rear of the cab on the outside of the cab, I think they are supposed to recirculate the air in the cab, I would like to also remove those vents to clean them and maybe install some type of screen if thats where the mice are coming from. I drive this truck every day and the mice are a weekly occurrence now. Thanks
Expert:  Mike S. replied 4 years ago.
Is that where the mice are at? In the vents. You probably want to remove the whole assembly and clean it real good and if you cant get rid of the smell replace what pieces you can't remove the smell from. I'll try to serach for what gets rid of mouse urine smell, but I am not going to guarantee anything will work. Also, I guess even before you replace anything you want to make sure they dont get in there again. Ok, let me look around and upload some diagrams that might help find out where they are getting in and also instructions and diagrams for removing the vents.
Expert:  Mike S. replied 4 years ago.

Heating, Ventilation, & Air Conditioning > Air Mix/Mode Actuator (Blend Door) > Removal & Installation

Removal & Installation

  1. Remove the floor air outlet duct extension (1) from the floor duct (2).

    Remove the floor air outlet duct extension (1) from the floor duct (2)

    Remove the floor air outlet duct extension (1) from the floor duct (2)

  2. Disconnect the electrical connection at the blend door actuator (10).

    Blend door actuator and related components

    Blend door actuator and related components

    Click to Enlarge
  3. Remove the blend door actuator mounting screws from the HVAC module.

  4. Remove the blend door actuator as an assembly with the actuator cam.

    Remove the blend door actuator mounting screws from the HVAC module

    Remove the blend door actuator mounting screws from the HVAC module

To install:

  1. Install the blend door actuator as an assembly with the actuator cam.

    • Line up the heater/defroster valve lever with the blend door actuator cam slot.

    • Line up the A/C valve lever with the blend door actuator cam

  2. Install the blend door actuator mounting screw to the HVAC module.

    • Tighten the blend door actuator mounting screw to 14 inch lbs. (1.6 Nm).

  3. Connect the electrical connection at the blend door actuator (10).

    Blend door actuator and related components

    Blend door actuator and related components

    Click to Enlarge
  4. Install the floor air outlet duct extension (1) to the floor air duct (2).

 

Expert:  Mike S. replied 4 years ago.

http://www.scoe10x.com/scripts/prodList.asp?idCategory=17

 

Some good reviews for getting the smell out.

Expert:  Mike S. replied 4 years ago.

All kinds of diagrams here. I am about a little more than halfway down the page still looking. Any signs of where they may be getting in, like maybe leaves stuck in the hole?

http://www.compnine.com/index.php?t=1&year=2003&majorgroup=16&supplgroup=NULL&catcode=56C&modelcode=C&makecode=LC&grouptype=B&modelid=7073&uid=1

 

Expert:  Mike S. replied 4 years ago.

Its going to be difficult for me to determine where they are getting in by looking at diagrams and guessing where they came in,but if you want diagrams of how things go together that is a good website for diagrams.

 

Mike S., Chevy Mechanic
Category: Chevy
Satisfied Customers: 4994
Experience: ASE Certified Master Technician
Mike S. and 5 other Chevy Specialists are ready to help you
Customer: replied 4 years ago.

Thank you Heavy Chevy 396, you have given me a lot of diagrams and info to get started, I rate you A -1 on my scale. You gave me the info, I wish you could give me the skill, I hate all this plastic crap. It's so much easier on my 61 Galaxie Sunliner.

Thanks again for helping a Ford guy.

Expert:  Mike S. replied 4 years ago.
Dont forget that www.compnine.com for diagrams. When you click on a picture it opens up another page. I wish there was a way I could tell you a way to check for mice footprints like on CSI, but I haven't seen that episode yet. Good Luck!

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