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Thread: Heater core replacement

  1. #1
    Join Date
    Sep 2012
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    Tallassee Alabama
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    74
    My Cars
    1996 BMW Z3

    Heater core replacement

    Well there is little doubt I have a leak in the heater core 1996 1.9 Z3. I have searched and found little information on how this is done on a Z3 except BMW says it is a 8-9 billable hour job.

    Going to start on it in the next couple of weeks and try to document the procedure for others on this forum but if anyone knows of a link to already posted details please let me know. Have decided to go with the OEM parts instead of the cheaper Spector as labor is the issue here more than saving a few bucks on parts.

  2. #2
    Join Date
    Oct 2012
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    Louisville, KY
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    4,503
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    1997 BMW Z3 1.9L 5MT
    I can only find info on it in the Bentley Manual...

    Z3 Heater Core RR.jpg
    BMW MOA 696, BMW CCA 1405

  3. #3
    Join Date
    Jul 2005
    Location
    Temecula Ca.
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    4,484
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    99 M Coupe LS Swap
    Get yourself a big bottle of pain killers. You are going to need them. Good luck with the project.
    Dan "PbFut" Rose

  4. #4
    Join Date
    Sep 2012
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    Tallassee Alabama
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    1996 BMW Z3
    Vintage 42 thanks do much for the page very helpful! I have no doubt about the pain killers at my age in that space well should be interesting!

  5. #5
    Join Date
    Sep 2012
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    Tallassee Alabama
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    1996 BMW Z3
    Ok I did it! Was going to post pictures but honestly the page from the Bentley manual is all you need to do this. Now why it tells you to raise the car and undo the heater hoses from the bottom I don't know at least in the case if the 1.9 that would be hard to do. The most difficult part was lining the tubes back up and making sure they were connected well. Not much room to work as you can imagine so frustrating at times rather than difficult. There was also a good bit if dirt and fluid residue to clean out if the area the core sits in showing the wet area collected more than I could have imagined in a car with 65k on it. If I had paid BMW the $1200 they wanted to do it I would have been mad as it took me about three hours taken allot of breaks as my 55 year s body needs these days.

    Here are some observations to think about first I spent the money on a factory BMW part which cost twice as much but did not want to take chances.

    For those if you who have trouble bleeding your system or your heater not working it may very well be a clogged heater core as mine was. My brother who works for Ford said that from day one last year when my troubles began with no heat or having to rev the motor to get heat. Never had a car that once the gauge got out of cold that I did not have heat and he said that is how all cars should work. As time went by small amounts if fluid became missing very little and I could not tell where it was going to. Even went to the point of having the fluid tested for oil and the oil tested for fluid.

    But as time went by the leak got worse to where even I could smell the antifreeze even though my wife had complained all along with that sensitive nose of hers. Soon small puddles showed up under the transmission and I had no heat at all so it could not be ignored any longer.

    After the new core was in new fluid added soon as the temp gauge got out if cold I had heat. No leaks no smell had not even bled the system yet and that is how your heater should work. After bleeding and checking and checking again no leaks no issues and ready to get back on the road!

  6. #6
    Join Date
    Aug 2015
    Location
    Denver, CO
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    3,181
    My Cars
    1999 Z3M, 1999 2.8 Coupe
    Anyone else done this job semi-recently? I get an occasional whiff of coolant (2.8 Coupe), with everything dry under the hood. I also replaced the heater hoses last time I had the manifold off, so I'm quite confident the core is the last original part in my heating/cooling circuit.

    I expected two gaskets, one for each line. Is there really only one? The Bentley snip above shows two, but RealOEM calls for one.

    https://www.realoem.com/bmw/enUS/sho...diagId=64_0659

    Edit: WTH? $198 for a gasket assembly???
    https://www.ecstuning.com/b-genuine-...t/64118398888/

    Plan was to pull driver's panels to get eyes on an actual leak before I drop $500 on a core and gasket.

    Alternatively, anyone know of a good aftermarket version? As long as it fits, a core is a core in my mind.
    Last edited by s8ilver; 06-16-2022 at 01:22 PM.
    Nathan in Denver

    1999 M Roadster, VFE V3 S/C, Randy Forbes Reinforced, Hardtop, H&R/Bilstein, Apex PS-7, Supersprint
    1999 Z3 2.8 Coupe, Headers, 3.46, Manual Swap, H&R/Koni, M Geometry/Brakes, M54B30 Manifold, Style 42

  7. #7
    Join Date
    Aug 2015
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    1999 Z3M, 1999 2.8 Coupe
    Oh, and I'll add that I just checked my level, and it's dead on full. The leak, if really there, must be miniscule. I also haven't run the heater in a while. Is the core bypassed when on cold?
    Nathan in Denver

    1999 M Roadster, VFE V3 S/C, Randy Forbes Reinforced, Hardtop, H&R/Bilstein, Apex PS-7, Supersprint
    1999 Z3 2.8 Coupe, Headers, 3.46, Manual Swap, H&R/Koni, M Geometry/Brakes, M54B30 Manifold, Style 42

  8. #8
    Join Date
    Jul 2009
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    Mesa, Arizona
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    749
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    2000 Z3 M-Roadster
    I assume you looked for coolant stalactites around the usual places?? I smelled coolant in one of my cars but could never find the leak until I was under the car doing other maintenance. There it was, a green coolant stalactite
    Tony
    "You can't sign away negligence."

  9. #9
    Join Date
    Dec 2018
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    North West, Indiana
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    00 M Roadster SC'ed
    I do believe a fair amount could accumulate under the carpet also.

  10. #10
    Join Date
    Aug 2015
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    1999 Z3M, 1999 2.8 Coupe
    Quote Originally Posted by ProductUser View Post
    I assume you looked for coolant stalactites around the usual places?? I smelled coolant in one of my cars but could never find the leak until I was under the car doing other maintenance. There it was, a green coolant stalactite
    Indeed. I've been through this (odd coolant leaks) a couple times already on the Coupe. All the usual under-hood suspects are bone dry. I only smell it with the heat on, but not all the time. With recent temps, heat isn't used at all. If there is a bypass, that makes perfect sense, but I'm not sure there is on these cars. Could the coolant be bypassed at the water valve with the heat off? Just the word "valve" in its part name would suggest so.

    - - - Updated - - -

    Quote Originally Posted by IndianaRoadster View Post
    I do believe a fair amount could accumulate under the carpet also.
    All dry to my knowledge, and I did have driver's seat out recently for my heat/lumbar retrofit. I guess it could accumulate under the center of the dash. I'll dig further. Studying photos of used cores, I could certainly see the O-rings as a possible leak point. What sizes those are, I have no idea. I did get a multipack of rings when I did my wife's AC compressor not long ago, so maybe a reseal is in my future. The $20 gasket set from BMW is now about $200. I'm also just tempted to buy a used $40 core on eBay to tinker with. Most still have the plastic gasket holder thingies still attached.
    Last edited by s8ilver; 06-16-2022 at 07:15 PM.
    Nathan in Denver

    1999 M Roadster, VFE V3 S/C, Randy Forbes Reinforced, Hardtop, H&R/Bilstein, Apex PS-7, Supersprint
    1999 Z3 2.8 Coupe, Headers, 3.46, Manual Swap, H&R/Koni, M Geometry/Brakes, M54B30 Manifold, Style 42

  11. #11
    Join Date
    Apr 2020
    Location
    Ankeny, IA
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    1,274
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    96 BMW Z3
    I've been losing about one notch on the reservoir every 700 miles and cannot track it down. I added UV tracer dye to the coolant and still nothing.

    My daily driver, a Chevy, smells like coolant every time we park it in the garage, but it hasn't lost a drop of coolant in thousands of miles.

    This is the dye I use: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

    And you'll need a cheap UV flashlight.
    Claude Berman, 96 Z3 Production Date 2/96 BMW CCA# 581686 Private Hudson : We're on an express elevator to hell, going down!

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