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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 186 (Heating, Ventilation, And Air Conditioning) >> Repair Instructions >> Flushing (NON-HP2) >> Flushing Procedure

Flushing Procedure

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    IMPORTANT: Warmer engine or ambient temperature decreases the refrigerant recovery time during the A/C flush procedure.
  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging (Non HP2)  or Refrigerant Recovery and Recharging (HP2) .
  2. Remove the orifice tube. Refer to Expansion (Orifice) Tube Replacement (W/O C69)  or Expansion (Orifice) Tube Replacement (W/C69)  or Expansion (Orifice) Tube Replacement (W/O C69-HP2)  or Expansion (Orifice) Tube Replacement (W/C69-HP2) .
  3. Connect the A/C lines with the orifice tube removed.
  4. Remove the A/C compressor. Refer to Air Conditioning Compressor Replacement (LY2, LY5, LH6, L76, L92 and LMG)  or Air Conditioning Compressor Replacement (HP2) .
  5. Inspect the end of the suction hose for a suction screen.
  6. Remove the suction screen, if installed.
  7. Install J 45268-4 to the A/C compressor suction hose.
  8. Install J 45268-5 to the A/C compressor discharge hose.
    9. Fig 1: View Of A/C Filter And Check Valve
    GM787687Courtesy of GENERAL MOTORS CORP.
  9. Forward flow refrigerant flushing is recommended for contaminated refrigerant or PAG oil.

    Perform the following procedure:

      IMPORTANT: The filter inside the J 45268-1 is serviceable. Remove and discard the check valve from the filter.
    1. Service the filter with ACDelco P/N GF 470, before each flush.

      Connect the J 45268-1 flush filter to the suction port of the J 45268-4 flush adapter.

    2. Connect the blue hose from the J 43600  to the J 45268-1 flush filter adapter. See Special Tools .
    3. Connect the red hose from the J 43600  to the J 45268-5 flush adapter. See Special Tools .
  10. Reverse flow refrigerant flushing is recommended for desiccant bag failure. Perform the following procedure and replace the accumulator when the flush procedure is complete.
      IMPORTANT: The filter inside the J 45268-1 is serviceable. Remove and discard the check valve from the filter.
    1. Service the filter with AC P/N GF 470, before each flush. Connect the J 45268-1 flush filter to the discharge port of the J 45268-5 flush adapter.
    2. Connect the blue hose from the J 43600  to the J 45268-1 flush filter adapter. See Special Tools .
    3. Connect the red hose from the J 43600  to the suction port of the J 45268-4 flush adapter. See Special Tools .
    11. IMPORTANT: Close the valve on the external refrigerant tank, before starting the flush process.
  11. Flush the front A/C system. Follow the instructions supplied with the J 43600  . See Special Tools .
    12. IMPORTANT: Flush the front A/C system before flushing the auxiliary A/C system.
  12. If the vehicle is equipped with rear A/C, flush the auxiliary A/C system separately.
    13. Fig 2: Cutting Orifice Tube Frame & Screen
    GM756678Courtesy of GENERAL MOTORS CORP.
  13. Cut the orifice tube frame and screen, enough to access the end of the orifice tube. Pinch off the orifice tube.
    14. Fig 3: Pinching Off Orifice Tube
    GM756680Courtesy of GENERAL MOTORS CORP.
    IMPORTANT: Pinch off the orifice tube in order to prevent refrigerant flow to the front system during the auxiliary system flush.
  14. Install the pinched orifice tube. Refer to Expansion (Orifice) Tube Replacement (W/O C69)  or Expansion (Orifice) Tube Replacement (W/C69)  or Expansion (Orifice) Tube Replacement (W/O C69-HP2)  or Expansion (Orifice) Tube Replacement (W/C69-HP2) .
  15. Remove the auxiliary thermal expansion valve (TXV). Refer to Auxiliary Air Conditioning Evaporator Thermal Expansion Valve Replacement .
  16. Install the J 45268-121.
    17. IMPORTANT: The auxiliary evaporator core can be flushed without totally reassembling into the auxiliary HVAC module.
  17. Install the auxiliary evaporator core to the A/C lines.
  18. Raise the vehicle. Refer to Lifting and Jacking the Vehicle .
  19. Connect the auxiliary A/C lines to the auxiliary evaporator core.
  20. Lower the vehicle.
  21. Flush the auxiliary A/C system. Follow the instructions supplied with the J 43600  . See Special Tools .
  22. Raise the vehicle. Refer to Lifting and Jacking the Vehicle .
  23. Remove the auxiliary A/C lines from the auxiliary evaporator core.
  24. Lower the vehicle.
  25. Remove the J 45268-121.
  26. Inspect the TXV for debris.

    Clean or replace as needed.

  27. Install the auxiliary TXV. Refer to Auxiliary Air Conditioning Evaporator Thermal Expansion Valve Replacement .
  28. Remove the J 45268-4 from the A/C compressor suction hose.
  29. Remove the J 45268-5 from the A/C compressor discharge hose.
    30. IMPORTANT: Flushing will remove all the PAG oil from the A/C system.
    The A/C system must be replenished with the correct amount of PAG oil.
  30. If the removed A/C compressor is being reinstalled, perform the following procedure:
  31. If you will replace the A/C compressor after flushing the system, perform the following procedure:
    1. Determine if the new service compressor is shipped with PAG oil. Refer to the Refrigerant System Capacities (Non-HP2) Refrigerant System Capacities (HP2)  .
    2. If the service compressor is shipped with PAG oil, DO NOT drain the new PAG oil from the compressor.
    3. Deduct the amount of PAG oil shipped with the service compressor from the amount of PAG oil listed in the capacities table. Refer to Refrigerant System Capacities (Non-HP2) Refrigerant System Capacities (HP2)  .
    4. Add the calculated amount to the compressor, as needed.
    32. IMPORTANT: Flushing will remove the fluorescent leak detection dye from the A/C system.
  32. Add one bottle of J 41447  directly to the A/C compressor. See Special Tools .
  33. Install the A/C compressor. Refer to Air Conditioning Compressor Replacement (LY2, LY5, LH6, L76, L92 and LMG)  or Air Conditioning Compressor Replacement (HP2) .
  34. Install a new orifice tube. Refer to Expansion (Orifice) Tube Replacement (W/O C69)  or Expansion (Orifice) Tube Replacement (W/C69)  or Expansion (Orifice) Tube Replacement (W/O C69-HP2)  or Expansion (Orifice) Tube Replacement (W/C69-HP2) .
  35. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging (Non HP2)  or Refrigerant Recovery and Recharging (HP2) .
  36. Leak test the fittings using J 42220  . See Special Tools .
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