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jazzmaster
jazzmaster, ASE Certified Tech
Category: GM
Satisfied Customers: 2951
Experience:  ase certified--32 yrs experience
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How do you change the heater core on a 1999 GMC Sierra

Customer Question

How do you change the heater core on a 1999 GMC Sierra
Submitted: 6 years ago.
Category: GM
Expert:  jazzmaster replied 6 years ago.

hi ,here is the procedure, ...guy...

REMOVAL PROCEDURE

  1. Drain the coolant. Refer to Draining and Filling Cooling System .
  2. Remove the instrument panel storage compartment.
  3. Disconnect the electrical connectors, as necessary.
  4. Remove the center floor air distribution duct.
  5. Remove the hinge pillar trim panels.
  6. Remove the blower motor cover.
  7. Remove the blower motor.
  8. Remove the steering column.
  9. Roll back the instrument panel. Refer to IP Carrier Replacement in Instrument Panel, Gauges and Console.
  10. Remove the coolant recovery reservoir.
  11. Remove the heater hoses.

While holding the heater case to the cowl, remove the screw on the interior side of the cowl, near the evaporator pipe, if equipped

  • On the engine side of the cowl, remove the 4 screws that hold the heater case to the cowl.
  • On the engine side of the cowl, remove the 2 nuts that hold the heater case to the cowl.
  • Remove the heater case. Ask an assistant for help, if necessary.
  • Remove the 7 screws that hold the heater cover to the heater case.
  • Remove the heater cover.
  • Remove the heater core from the retainer
  • THIS IS FOR THE INSTRUMENT PANEL (BELOW) DO THIS FIRST
  •  

  • Remove the knee bolster.
  • Remove the knee bolster reinforcement.
  • Remove the knee deflector bracket.
  • Remove the tubular tie bar from under the steering column.
  • Remove the steering column.
  • Remove the IP storage compartment door
  •  

    Remove the 2 bolts from the PSIR bracket

     

  • Remove the left and the right lower instrument panel pivot bolts.
  •  

  • Remove the center support screw.
  • Pivot the instrument panel
  • Expert:  jazzmaster replied 6 years ago.
    did this help you ...guy..