BMW 318/325/M3/525/535/M5 1989-1993 Repair Information

Heater Core

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REMOVAL & INSTALLATION



E30 3 Series
  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.  
  3. Loosen the coolant pipe clamp near the heater connection.
  4.  
  5. Remove the duct from the heater to the rear heating duct.
  6.  
  7. 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.
  8.  
  9. Remove the heater core bolts and remove from the heater housing.
  10.  

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.  

E36 3 Series

See Figures 1 through 5



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Fig. Fig. 1: Remove the nut to disconnect the water flange-E36 3 Series



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Fig. Fig. 2: Remove the nut and the O-rings from the flange-E36 3 Series



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Fig. Fig. 3: Remove the trim screws before disconnecting the lower trim-E36 3 Series



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Fig. Fig. 4: Remove the bolt to disconnect the flange at the heater core-E36 3 Series



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Fig. Fig. 5: Remove the screw to withdraw the heater core-E36 3 Series

  1. Turn the ignition switch to the OFF position. Remove the air intake cowl weather-stripping. Remove the grill by gently prying out.
  2.  
  3. Remove the 2 screws inside the air intake cowl holding the electrical duct.
  4.  
  5. Remove the 2 screws holding the right side of the air intake cowl and remove the screw holding the left side. Pull the cowl out from above. It may be very hard to remove, but it will come out.
  6.  
  7. Remove the nut from the heater connection and pull off the connection. Blow air into the intake hose to force the coolant out of the heater core. This will prevent coolant from dripping onto the carpeting.
  8.  
  9. Remove the nut from the connection in the engine compartment. Remove the screws from the left, lower instrument trim panel and pry off.
  10.  
  11. Remove the screw from the pipe connection at the heater core. Remove the heater core mounting nut and remove the heater core.
  12.  

To install:
  1. Replace the heater core and the mounting screw. Replace the O-rings on the pipe connection and install the mounting bolts.
  2.  
  3. Install the trim panel and screws. Install the nut on the engine compartment side of the pipe connection.
  4.  
  5. Replace the O-rings on the connection and install the flange and nut.
  6.  
  7. Install the air intake cowl and screws. Replace the electrical duct screws and the intake grill. Install the weather-stripping.
  8.  

E34 5 Series
  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.  
  5. Remove the screws from the holder. Remove the screws from the right holder and remove the holder.
  6.  
  7. Remove the motor for the front vents and disconnect the inside temperature sensor.
  8.  
  9. Disconnect the screws, straps and clips holding the heater cover. Remove the cover to expose the internal coolant pipes.
  10.  
  11. Remove the mounting screws from the coolant pipes and lift out. The heater core remove from the right.
  12.  

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.  

 
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