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  1. #1
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    Glasgow, , United Kingdom
    Member No: 141691 72DC is an unknown quantity at this point 72DC's Avatar
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    Coolant leaking into ventilation system


    I am new to the board but am an avid fan of Roadfly forums having owned several E34s, and E39s and found the support and help from members invaluable.

    My father's 1990 E32 is leaking coolant into the ventilation system. The windscreen is misting and there is a gurgling sound coming from the ducts that feed the rear fresh air vent. When the blower is on liquid is sprayed out the vent. After scouring the archives I have concluded that the most likely cause is some form of leak from the heater core, o ring or inlet pipes. Before I start tearing apart the dash to get to the heater core I am trying to eliminate all possible causes as the dash removal looks horrific. Could coolant be entering the air intake for the ventilation system from the engine bay and if so where should I look? (the archives do not have any info on this)

    In addition I have heard of a shortcut method of accessing the heater core. Can anyone advise how this is achieved. Old links to heater core replacement guides are broken. Can anyone send me the info?

    Thanks to all in advance.


  2. #2
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    Member No: 14327 Highline is an unknown quantity at this point Highline's Avatar
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    heater core replacement

    use this link


    Since the weather was nice I decided to tear into the dashboard.
    My symptoms: low coolant message after a few days when using the heater. No coolant on ground. Positive smell in cabin but no mist on windows as often described.
    My findings: small corrosion at top of passenger heater element.
    Tips: One does not have to remove the upper dashboard as mentioned on a 7 series page. The center rear and forward console has to be completely removed. The black panel holding radio, climate control and computer can be swung out of the way while disconnecting radio and climate control and lighter keeping computer connected. The components don't have to come out individually. Behind this is the plastic covering over the heater core with 10 clips and a few screws. As I didn't use the heat for 5 momths it can be removed without draining coolant or clamping the firewall hoses but place some paper towels under it as the core is leaned forward and lifted out. I let about 1/8 cup of coolant drip while replacing the towels. Clean all inside plastic surfaces well to get rid of coolant vapor residue. Use new rubber washers on the pipe connections (usually supplied but if not buy some). Assembly is reverse of removal. Don't forget to reconnect the cigarette lighter (I did and now have to figure out how to reconnect it with minimal disassembly).
    Total time to replace and reassemble: 4 hours. I took five however, spending time to clean all switches and dashboard parts on reassembly.

    I didn't document with photos but in case anyone wants to tackle the heater core replacement, here are some instructions. Perhaps it will be good for the archives at any rate. I, of course imply no guarrantees of success and take no responsibility for your peril (I'm not a lawyer). But seriously, it's not too hard.
    Tools: Philips #1 and #2. Socket or wrench 8 or 9mm and 13mm. Small straight blade screwdriver for prying. Flashlight.

    1. Pry off vertical black strips to right and left of center black console housing the radio, etc to reveal screws.
    2. Pry off wood dashboard strips below instruments to reveal screws.
    3. Remove drivers lower dash panel via 6 screws
    4. Open/lower glovebox (can keep attached by straps).
    5. Remove shifter knob, leather boot surround, wood surround (reach hand in and pop up forward edge, slide forward and up (towards ash tray) to clear tabs at edge of wood closest to you).
    6. Remove rubber and foam around shifter rod.
    7. Pry off color-coded cap from screw at junction of front and rear consoles (where center recess is between arm rests).
    8. Unscrew said screw.
    9. Pry off leather parking brake surround and lift up a little.
    10. Unscrew screw at bottom of opening around parking brake which holds down driver's side of front console to rear console.
    11. Pry off rear black panel where rear airducts are located.
    12. Use 8 or 9mm socket to unscew two side bolts holding rear console in place (I couldn't easily budge the 2 phillips screws but this is an alternate).
    13. With rear console free, slide it back 5 inches but don't need to lift up.
    14. Using 8-9 mm socket, unscrew black plastic bolt holding rear of front console in place on a ridged plastic tab.
    15. Up front, unscrew single phillips screw holding small carpet piece along right and left sides of transmission tunnel (e.g. near accelerator pedal) and slide piece of carpet forward and lift off.
    16. Unscrew black phillips screw holding front bottom of center console to a brass metal tab on both sides.
    17. Unscrew any of the four remaining screws at black plastic console holding radio, climate control, etc., revealed in step #1
    18. Attempt to free the front center console. The window switches need to be pried up and disconnected along with the hazard switch. I don't have ASC but this switch, if present, should be disconnected. Un plug white connector holding wires to cigarette lighter.
    19. Try to swing upper center black console containing radio to the right. As you do so, disconnect radio wires, climate control cables, and climate control wires. Look at how connectors come off carefully; one has a small lever that needs to be pulled which helps eject it. I didn't disconnect the computer but this could also be done.
    20. Swing this assembly to the right and balance on open door of glove box (don't scratch your wood - use a protective paper, cloth, etc.
    21. Revealed is now a big black plastic enclosure to the heater core. Disconnect temperature wires at white connectors on each side.
    22. Unscrew two phillips screws at front base of enclosure.
    23. Un-bolt two shock absorbing mounts at base of front enclosure.
    24. Remove 10 clips holding enclosure back (facing you) to the front half. The clips at driver's side may be tough to spot and access due to the obvious wires and metal support rod, but this is "do-able".
    25. Clip tie wraps holding t-shaped wire loom in front of enclosure and push this and climate control cables up, out of your way.
    26. Remove enclosure panel. Start at passenger side and pull towards you, then slide to passenger side and free driver's (left side) from behind wiring etc.
    27. Now you see heater core!
    28. Un-screw each of three pipes slowly and make sure paper towels are on hand. I didn't drain coolant and did lose 1/4 cup from top of core and pipes, but that's all. Make sure towels soak up any draining coolant and not your carpeting.
    29. carefully bend/move passenger element pipe torwards you to make room for removing core (just a little).
    30. Core is only held in place by the three pipes. Pull top of core forward torwards you and lift out of dashboard.
    31. Clean plastic box well.
    32. Have three new washers on hand for attaching new core and pipes.
    33. Test the new core to rule out leakage by reattaching the climate control and running the car.
    34. Assembly, is, well reverse of above.
    35. Bleed the coolant system.
    I hope I haven't missed anything. Good luck.





    Shogun E32 Tech Tips: http://twrite.org/shogunnew/topmenu.html

  3. #3
    Registered Member
    Glasgow, , United Kingdom
    Member No: 141691 72DC is an unknown quantity at this point 72DC's Avatar
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    Re: heater core replacement

    Great, thanks for that Shogun. Oh well, time to get up to my elbows in dashboard.

    72 DC

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