Mazda Trucks 1972-1986 Repair Guide

Evaporator Core

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REMOVAL & INSTALLATION




CAUTION
Please refer to General Information And Maintenance before discharging the compressor or disconnecting air conditioning lines. Damage to the air conditioning system or personal injury could result. Consult your local laws concerning refrigerant discharge and recycling. In many areas it may be illegal for anyone but a certified technician to service the A/C system. Always use an approved recovery station when discharging the air conditioning.

  1. Discharge the refrigerant system. See General Information And Maintenance .
  2.  
  3. Disconnect the battery ground cable.
  4.  
  5. Drain the cooling system.
  6.  


CAUTION
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 quantity. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  1. Remove the water valve shield at the left side of the heater.
  2.  
  3. Disconnect the two hoses from the left side of the heater.
  4.  
  5. Using a back-up wrench, disconnect the refrigerant lines at the core connectors. Plug all openings at once!
  6.  
  7. At the heat-defroster door, the water valve and the outside recirculation door, disengage the control cable housing from the mounting clip on the heater. Disconnect each of the three cable wires from the crank arms.
  8.  
  9. Disconnect the fan motor electrical lead.
  10.  
  11. Remove the glove compartment for clearance.
  12.  
  13. Working inside the engine compartment, remove the fasteners which hold the heater/evaporator case to the firewall. Later models also have a retaining bolt inside the passenger compartment which must be removed.
  14.  
  15. Disconnect the defroster ducts from the heater/evaporator case and remove the unit.
  16.  

To install:
  1. Install the unit on the firewall so that the heater duct indexes with the air intake duct and the two mounting studs enter their respective holes.
  2.  
  3. From the engine side of the firewall, install the fasteners. While an assistant holds the unit in position, install the mounting bolts.
  4.  
  5. Connect the defroster ducts.
  6.  
  7. Connect the heat-defrost door control cable to the door crank arm. Set the control lever (upper) in the HEAT position and turn the crank arm toward the mounting clip as far as it will go. Engage the cable housing in the clip and install the screw in the clip.
  8.  
  9. Connect the water valve control cable wire to the crank arm on the water valve lever. Locate the cable housing in the mounting clip. Set the control lever in the HOT position and pull the valve plunger and lever to the full outward position. This will move the lever crank arm toward the cable mounting clip as far as it will go. Tighten the clip and screw.
  10.  
  11. Insert the outside recirculation door control cable into the hole in the door crank arm. Bend the wire over and tighten the screw Set the center control lever in the REC position and turn the door crank arm toward the mounting clip as far as it will go. Engage the cable housing in the clip and install the screw in the clip.
  12.  
  13. Connect the fan motor electrical lead.
  14.  
  15. Using a back-up wrench and new O-rings coated with clean refrigerant oil, connect the refrigerant lines to the core tubes.
  16.  
  17. Connect the two hoses to the heater core tubes, at the left side of the heater, and tighten the clamp.
  18.  
  19. Install the water valve shield and tighten the three screws (left side of the heater).
  20.  
  21. Refill the cooling system and connect the battery ground cable.
  22.  
  23. Evacuate, charge and leak-test the refrigerant system. See General Information And Maintenance .
  24.  
  25. Run the engine and check for leaks. Check the operation of the heater.
  26.  
  27. Replace the glove compartment.
  28.  

 
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