BMW Coupes and Sedans 1970-1988 Repair Guide

Heater Core

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REMOVAL & INSTALLATION



1600, 2000, 2002 and 320 i Models

In order to remove the heater core, it is necessary to first remove the entire heater assembly from the car. See the procedure for removing the blower motor, above. Once the heater is out of the car, the core may be removed by drilling out the rivets and unsnapping the clips which hold the housing halves together.

2500, 28000, Bavaria, 3000 and 3.0 Models
  1. Drain the coolant from the system.
  2.  


CAUTION
When draining 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 the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect the heater hoses from the heater core, and remove the rubber seal.
  2.  
  3. Remove the fresh air outlet grille cover.
  4.  
  5. Remove the heater control cover.
  6.  
  7. Disconnect the air distribution hoses from the discharge nozzles.
  8.  
  9. Remove the intermediate distribution duct.
  10.  
  11. Remove the buttons from the control levers.
  12.  
  13. Remove the threaded knobs for the left instrument panel trim strip.
  14.  
  15. Remove the rear switch plate.
  16.  
  17. Remove the front switch plate.
  18.  
  19. Remove the heater retaining nuts.
  20.  
  21. Tilt the heater and switch plate inwards, and remove the heater.
  22.  
  23. Detach the cable going to the defroster flap.
  24.  
  25. Pull off the retaining clips, remove the seals, and pull apart the halves of the heater housing (the core will stay in the left side of the housing).
  26.  
  27. Slide the core out of the housing, pulling the outer end toward you to permit the hose connections to clear the housing.
  28.  

To install:
  1. Reverse the removal procedure, noting the following points:
    1. Slide the air guide baffle in an angle to properly install.
    2.  
    3. First insert the switch plate into the dash and then insert the heater. Tighten the attaching nuts firmly. Check the foam rubber seal between the heater and dash panel and replace, if necessary.
    4.  
    5. When installing the front switch plate, make sure the control levers do not scrape against the trim.
    6.  
    7. Replace the sealing gasket which goes under the cowl cover.
    8.  

  2.  

3 Series Models
  1. Disconnect the negative battery terminal. Remove the center console and the drivers side instrument panel trim next to the steering column. Drain the coolant.
  2.  


CAUTION
When draining 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 the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Loosen the coolant pipe clamp near the heater connection.
  2.  
  3. Remove the duct from the heater to the rear heating duct.
  4.  
  5. Place some rags or a small container under the heater connection to catch any spilled coolant. Remove the bolts from the heater connection and separate the joint.
  6.  
  7. Remove the heater core bolts and remove from the heater housing.
  8.  

To install:
  1. Replace the heater core into the heater housing and replace the bolts. Replace the O-rings on the heater pipe joint. Connect the pipe to the heater core and install the bolts.
  2.  
  3. Install the rear heating duct connection and the pipe holding clamp. Install the instrument panel trim and the center console. Fill the cooling system and bleed. Connect the negative battery terminal.
  4.  

5 Series Models
EXCEPT 528i AND 530i MODELS
  1. Remove the center console and the glove compartment.
  2.  
  3. Disconnect the coolant hoses from the heater. The upper hose is the return line, the middle hose the water feed for the right side and the bottom is the feed for the left side. Blow air into the return connection to remove the remaining coolant from the core.
  4.  


CAUTION
When draining 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 the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the screws from the holder. Remove the screws from the right holder and remove the holder.
  2.  
  3. Remove the motor for the front vents and disconnect the inside temperature sensor.
  4.  
  5. Disconnect the screws, straps and clips holding the heater cover. Remove the cover to expose the internal coolant pipes.
  6.  
  7. Remove the mounting screws from the coolant pipes and lift out. The heater core remove from the right.
  8.  

To install:
  1. Install the heater core and the coolant pipes with new O-rings. Install the cover and connect the clips, straps and screws.
  2.  
  3. Install the vent motor and connect the inside temperature sensor. Install the holders and screws.
  4.  
  5. Connect the coolant hoses. Install the center console and glove compartment. Fill and bleed the cooling system.
  6.  

528i AND 530i MODELS

  1. Remove the center tray.
  2.  
  3. Remove the glove box.
  4.  
  5. Disconnect the battery ground.
  6.  
  7. Push the selector lever to the WARM position.
  8.  
  9. Drain the coolant.
  10.  


CAUTION
When draining 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 the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect the heater hoses from the heater core, and remove the rubber seal.
  2.  
  3. Remove the lower instrument panel center trim.
  4.  
  5. Disconnect the heater controls at the instrument panel.
  6.  
  7. Disconnect the control shafts at the joints. To do this, press in locking prongs with needle nose pliers.
  8.  
  9. Unfasten the multiple electrical connector at the heater.
  10.  
  11. Remove the instrument panel center cover.
  12.  
  13. Working from inside the engine compartment, remove the upper section of the fire shield.
  14.  
  15. Disconnect ducts by pulling outward to pull connector pins out of bushings which are in the ducts.
  16.  
  17. Remove clips and remove the outer portion of the lower blower housing. Pull out the motor/blower unit, disconnect the wires, and remove it.
  18.  
  19. Pull the foam rubber seal about halfway off and fold back.
  20.  
  21. Remove the clamp from the pipe leading to the water valve, disconnect the water valve and remove the valve and pipe as an assembly.
  22.  
  23. Remove clips and detach the right side housing. Note this housing covers ears which operate the heater damper.
  24.  
  25. Remove the attaching circlip and remove the smaller gear. Then, pull out the shaft to which the smaller gear is mounted.
  26.  
  27. Remove the housing clips and separate the housing halves.
  28.  
  29. Press out the grommet and pull the wires out from between core pipes and the core. Remove the core from the heater assembly.
  30.  

To install:
  1. Reverse the above, keeping the following points in mind:
    1. Glue new rubber seals onto the outside of the core before installing it into the heater.
    2.  
    3. When reassembling the halves of the heater, first position the sleeve on the air flap and position the flap carefully and guide it into the bore on the opposite side of the heater housing.
    4.  
    5. When reinstalling damper gears, mesh the gears so the timing marks line up.
    6.  
    7. Replace the water valve seals.
    8.  
    9. When remounting the lower blower motor, make sure the portion of the motor between the 2 electrical connectors engages with the slot in the heater housing. Then, when reinstalling the blower housing, make sure the flat surface on either side of the intake duct faces down.
    10.  
    11. Secure the cables so that air flaps are closed when the control switch is at OFF .
    12.  
    13. Turn the fan switch and water valve and air distribution flaps left to the stop for each when reconnecting the control shafts.
    14.  

  2.  

733i and 735i Models
  1. Drain coolant from the cooling system.
  2.  
  3. Remove the center console.
  4.  


CAUTION
When draining 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 the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the 2 bolts and remove the right core mounting bracket. Lift out the front blower motor.
  2.  
  3. Remove the core cover screws. Loosen the wire straps and clips and remove the cover.
  4.  
  5. Unscrew the 6 mounting bolts and lift out the 3 heater pipes. Replace the O-rings. Then, lift out the core from the right side.
  6.  

To install:
  1. Install core by reversing the above procedures. Check all connections for leaks and check the system for correct operation.
  2.  

 
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