Page 2 of 3 FirstFirst 123 LastLast
Results 26 to 50 of 51

Thread: Thermostat Housing Leaks After Replacing Thermostat

  1. #26
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    Quote Originally Posted by thenjnick View Post
    Sorry I dont mean to threadjack...


    Sent from my iPhone using Tapatalk
    I already noticed that. I'm cool with it.

  2. #27
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    Quote Originally Posted by thenjnick View Post
    Agreed. I topped it off and bled it yesterday, ran it for a while with no overheating. Ill check the level tomorrow.



    I honestly don’t know what happened prior to it shooting into the red, I tried to get more info but no go. I think trapped air is a good bet, however the aux fan isn’t being triggered by the temp switch or the AC plus it was a hot day so that’s most likely the cause. Could there be such a large air pocket that left me over a liter dry on coolant even after driving it a few days without issue? I did drain the block too..still seems odd to me

    Im just worried about the condition of the head gasket at this point. The car has overheated a few times now and im hoping to do a compression/leak down test soon.


    Sent from my iPhone using Tapatalk
    Sounds like you have a leak.

    - - - Updated - - -

    Quote Originally Posted by Migou View Post
    When I changed my t/stat housing I sanded it flat before installing. Even brand new it was a bit warped. Granted it was on a 6 cyl.
    If the new housing I ordered is warped, I'm just gonna return it and use the old housing with a butt ton of RTV.

  3. #28
    Join Date
    Apr 2017
    Location
    NJ
    Posts
    229
    My Cars
    1995 318ic

    Thermostat Housing Leaks After Replacing Thermostat

    I really hope not. I wouldnt be surprised though, I take that poor car to redline almost every time i drive it..
    Last edited by thenjnick; 08-12-2018 at 01:32 PM.

  4. #29
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    While I'm patiently waiting for my new thermostat housing to arrive, I went out and purchased some thermal silicon rtv. I have one question though. The directions state to apply the rtv on both sides of the gasket, then hand tighten the housing and let set for one hour. Then tighten the housing all the way. Then takes 24 hours to cure. Wha what?

    Do I honestly need to wait 24 hours?

  5. #30
    Join Date
    Feb 2002
    Location
    Orlando, FL
    Posts
    8,884
    My Cars
    Turbo 97 E36 M3, 99 M3
    I dont put any RTV on the gasket. The gasket will seal fine. I put a very thin layer of RTV around the edge of the housing, install, and let it settle while I finish up installing everything, take a break, come back after an hour and should be fine. Make sure you follow the directions to cure, all surfaces are clean, bolts are torqued correctly, and you should have no issues. The 10mm bolts are 89 in/lbs and the 13mm? that holds the hoist bracket are 16 ft/lbs.
    1997 Arctic Silver/Black M3
    CES Stage IV (651rwhp/615rwtq @ 24 psi)

    1999 Techno Violet/Dove M3
    Auto/Convertible and staying stock!

  6. #31
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    I just installed the new thermostat housing, used enough RTV so it oozes from the gasket, let cure for an hour. Torqued to 89in/lb then topped up antifreeze bit by bit. Started engine and after a few minutes, antifreeze is leaking out worse than with the old housing.

  7. #32
    Join Date
    Apr 2017
    Location
    NJ
    Posts
    229
    My Cars
    1995 318ic
    From the housing? Still?? Is it sitting flush against the head? I don’t see how that’s possible unless the system is under an unusual amount of pressure and or the mating surface itself is somehow damaged.


    Sent from my iPhone using Tapatalk

  8. #33
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    Quote Originally Posted by thenjnick View Post
    From the housing? Still?? Is it sitting flush against the head? I don’t see how that’s possible unless the system is under an unusual amount of pressure and or the mating surface itself is somehow damaged.


    Sent from my iPhone using Tapatalk
    It seems flush mounted to me. Everything tightened up evenly unlike the old housing. Maybe its the gasket. I only applied RTV to one side of it.

  9. #34
    Join Date
    Apr 2017
    Location
    NJ
    Posts
    229
    My Cars
    1995 318ic
    Huh.. maybe the RTV just wasn’t sealing up completely before it tacked up after an hour? Just seems odd because I didn’t use any on my gasket..


    Sent from my iPhone using Tapatalk

  10. #35
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    Quote Originally Posted by thenjnick View Post
    Huh.. maybe the RTV just wasn’t sealing up completely before it tacked up after an hour? Just seems odd because I didn’t use any on my gasket..


    Sent from my iPhone using Tapatalk
    You could be right. I waited an hour and fifteen minutes after RTV and the coolant started leaking after about five minutes. I waited another hour and a half and nothing leaked for a good ten minutes. I thought I was home free but glad I waited because five minutes later, a small leak started appearing from the top again.
    Last edited by donb318; 08-26-2018 at 10:21 PM.

  11. #36
    Join Date
    Apr 2015
    Location
    Sacramento CA
    Posts
    403
    My Cars
    2001 Z3 Roadster
    Let it sit overnight.

  12. #37
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    Quote Originally Posted by Migou View Post
    Let it sit overnight.
    You read my mind.

  13. #38
    Join Date
    Oct 2012
    Location
    Detroit, MI
    Posts
    1,977
    My Cars
    E36, E70, i3
    It probably varies based on brand, but the RTV I used recommended letting it cure for 24 hours before even filling, let alone running.

  14. #39
    Join Date
    Feb 2002
    Location
    Orlando, FL
    Posts
    8,884
    My Cars
    Turbo 97 E36 M3, 99 M3
    Where, specifically, is it leaking from? Is the new cover Uro brand? You shouldnt have to cake RTV on the housing, just a thin layer. You do have a seal on the Tstat itself and installed with the arrow pointing up, right? Coolant isnt viscous like oil, so if you have a leak, you either dont have flat mating surfaces, dont torque the nuts correctly, or there is something obvious we are missing. At 5/10 minutes of running, are you getting up to temp? Too much pressure?
    1997 Arctic Silver/Black M3
    CES Stage IV (651rwhp/615rwtq @ 24 psi)

    1999 Techno Violet/Dove M3
    Auto/Convertible and staying stock!

  15. #40
    Join Date
    Oct 2012
    Location
    Detroit, MI
    Posts
    1,977
    My Cars
    E36, E70, i3
    Helps if I read. Yes you should've waited 24 hours.

  16. #41
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    Damnit it's still leaking at the top. . I can see a small leak bubbling out a tiny hole at the top. I have it plastered with red RTV oozing out though. Might be the hole from the previous leak when it was curing. Maybe I'll dab some more RTV just at that spot. Doesn't seem like I should need to do all of that though. Also, I must admit I did not pristine clean the engine side but it did not look terribly bad. I figured the RTV would seal it good enough.

  17. #42
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    Quote Originally Posted by BMWManiac View Post
    Where, specifically, is it leaking from? Is the new cover Uro brand? You shouldnt have to cake RTV on the housing, just a thin layer. You do have a seal on the Tstat itself and installed with the arrow pointing up, right? Coolant isnt viscous like oil, so if you have a leak, you either dont have flat mating surfaces, dont torque the nuts correctly, or there is something obvious we are missing. At 5/10 minutes of running, are you getting up to temp? Too much pressure?
    New housing is supposed to be genuine BMW but I'm doubting it is. It was super clean and was not warped though. It is leaking coolant from the top only. About a quarter inch leak. Tstat is arrow up with seal. Thousing has gasket with two thin RTV beads. Engine takes 6-7 minutes at idle to get up to temp and then it leaks.
    Last edited by donb318; 08-28-2018 at 12:06 AM.

  18. #43
    Join Date
    Aug 2013
    Location
    Seattle, WA
    Posts
    1,433
    My Cars
    1999 BMW M3 Coupe
    Just chiming in to say that you shouldn't need any RTV with an OEM plastic housing and gasket. It should seal right up if everything is clean and you install it correctly. I'm pretty sure BMW didn't use any at the factory. The aftermarket aluminum housings do need RTV because they're cheap and don't seal very well, and even then they leak much more often than OEM.

    *This is from my 6 cylinder knowledge, so I guess it could be different on a 4 cylinder (though I doubt it).
    Last edited by TostitoBandito; 08-28-2018 at 12:26 PM.
    1999 M3/2/5 - Titanium Silver - Track/Weekend Toy


  19. #44
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    Quote Originally Posted by TostitoBandito View Post
    Just chiming in to say that you shouldn't need any RTV with an OEM plastic housing and gasket. It should seal right up if everything is clean and you install it correctly. I'm pretty sure BMW didn't use any at the factory. The aftermarket aluminum housings do need RTV because they're cheap and don't seal very well, and even then they leak much more often than OEM.

    *This is from my 6 cylinder knowledge, so I guess it could be different on a 4 cylinder (though I doubt it).
    I did not know that about the aluminum housings. I would have went plastic but the housing part number referenced aluminum.

    I found out what I did wrong. When I added coolant too early (prior to 24 hour) and it leaked out the top, I did not seal that leak. I just let the RTV cure overnight. I believe that same leak did not magically close itself off though. Yeah back to the drawing board for me. I just did not feel like removing the housing and scrapping the RTV off. I have already spent way too much time on this repair.

    The engine side looked like this, https://flic.kr/p/MHDYQm, does it look clean enough? I did not think it needed to be pristine clean and so I left it alone.

  20. #45
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    I just called my mechanic and he said plastic housings leak. He also said I do not need RTV. I think I am just going to take it to him because I am tired of messing with it. He's not going to charge much to fix it. I tried.

  21. #46
    Join Date
    Aug 2013
    Location
    Seattle, WA
    Posts
    1,433
    My Cars
    1999 BMW M3 Coupe
    Sure, everything will leak eventually if given enough time.

    Either an OEM plastic or aluminum housing should give you many years of leak-free service. The major difference between the two is that it's usually trickier to get the aluminum housings sealed properly since they rely on RTV to some extent and have rougher surfaces with more manufacturing variations. Yes the OEM plastic housings can sometimes crack (usually only after 10-20+ years), and the gaskets/sealant can eventually leak after many years on both types, but the OEM plastic housings should usually be more trouble-free to install.

    It's mainly an aesthetic choice. If you want the prettier aluminum housing and are willing to deal with potentially more labor getting it to initially seal properly and not leak, go for it. If you don't care about looks, just get the OEM part and gasket. It's what was on the car from the factory, and if you follow the same procedures (see Bentley manual) it should be like new.
    Last edited by TostitoBandito; 08-28-2018 at 03:30 PM.
    1999 M3/2/5 - Titanium Silver - Track/Weekend Toy


  22. #47
    Join Date
    Apr 2017
    Location
    NJ
    Posts
    229
    My Cars
    1995 318ic
    I wire brushed mine off on both sides pretty good because im so anal. I think you should try a new elring gasket with the sealant already beaded on with either no extra RTV or just a very thin layer on the housing side and let it cure for a good 24 hours before doing anything to the car. Not sure what brand of sealant you are using but I have a few different tubes of permatex laying around and they all recommend 24 hours for curing. Good luck, that sucks that you’ve had so much trouble with this..


    Sent from my iPhone using Tapatalk

  23. #48
    Join Date
    Apr 2011
    Location
    San Diego, CA
    Posts
    162
    My Cars
    '06 530i, '16 320i
    UPDATE:
    I just got my car back from my mechanic's today and he said.... brace yourself... I did not remove the old thermostat housing gasket from the engine side. Umm I did but I think he meant I did not remove all of it pristine-like. Well it seemed clean enough for me but I guess it had to be sparkling clean. Lesson learned.
    Last edited by donb318; 09-14-2018 at 09:23 PM.

  24. #49
    Join Date
    Jan 2010
    Location
    Sonoma Whine Country
    Posts
    1,767
    My Cars
    E12, E12, E36, E39
    Quote Originally Posted by donb318 View Post
    UPDATE:
    I just got my car back from my mechanic's today and he said.... brace yourself... I did not remove the old thermostat housing gasket from the engine side. Umm I did but I think he meant I did not remove all of it pristine-like. Well it seemed clean enough for me but I guess it had to be sparkling clean. Lesson learned.
    If you can feel it with your fingernail, it's not clean enough. And no RTV please, that's the sure mark of an amateur. In a very few applications it works great, but it's used 1000 times when it shouldn't be.
    98 328is
    02 525ita
    80 528i
    81 528ia
    and decades of owning and driving BMWs

  25. #50
    Join Date
    May 2012
    Location
    Central Wisconsin
    Posts
    640
    My Cars
    '94 325i, '93 325is
    Carbide scraper is the tool for cleaning surfaces for new gaskets. You will wonder what you did without one.
    '94 325i Sedan, Arctic Gray: UUC LTW FW, EVO 3 and DSSR, +.020 Maxsil pistons, ASC delete, Eibach shocks/springs, 16" contour reps 238k
    '93 325is Coupe, Schwarz, work beater 299k
    '89 325i Vert, Alpine White: 5spd swapped. Sold
    '04 Toyota Sienna XLE Limited AWD, In progress swapping to M50/G250, http://www.wibimmers.com/board/index...nna-25i-build/
    '05 Volvo V70 R, 6mt, mostly stock, kid hauler 200k Sold
    '85 Toyota LandCruiser: Lifted, gas hog. 205k

Page 2 of 3 FirstFirst 123 LastLast

Similar Threads

  1. Replaced M42 318i thermostat, housing leaking. Use sealant?
    By Not Sure in forum 1991 - 1999 (E36)
    Replies: 8
    Last Post: 01-17-2011, 01:57 PM
  2. Aluminum Thermostat Housing leaking after 1k miles
    By juiceman in forum 1996 - 2003 (E39)
    Replies: 13
    Last Post: 05-05-2009, 05:29 AM
  3. Coolant leak around thermostat cover after replacing thermostat
    By DSrugis in forum 1992 - 1999 M3 (E36)
    Replies: 1
    Last Post: 06-28-2008, 08:02 PM
  4. Coolant leak after replacing radiator, thermostat, water pump
    By Hawkman in forum 1992 - 1999 M3 (E36)
    Replies: 13
    Last Post: 04-18-2008, 06:29 PM
  5. Coolant level-after replacing thermostat
    By ScottDetroit in forum 1992 - 1999 M3 (E36)
    Replies: 1
    Last Post: 10-04-2001, 06:31 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •