Results 1 to 21 of 21

Thread: E39 540 - confirm orientation of PS hoses at cooler

  1. #1
    Join Date
    Dec 2015
    Location
    Boston, MA
    Posts
    109
    My Cars
    2007 BMW 530xiT

    E39 540 - confirm orientation of PS hoses at cooler

    Hi, Everyone-

    I'm slowing tracking down the source of several power steering leaks. I had a leak at the bottom of the reservoir and replaced the reservoir along with the return hose (reservoir bottom to cooler) and this has fixed one leak. The other hose at the cooler (to the rack) is also leaking where the soft rubber part meets the metal flange (near the cooler).

    Here's my question:

    The cooler inlet has two holes - one for the hose going to the reservoir and one for the hose going to the rack. On mine, the return line that goes back to the reservoir is on the BOTTOM INLET to the cooler and the hose to the rack (with the locking tab) is on the TOP INLET to the cooler. Interestingly, realoem (link below) shows them oriented the other way (reservoir hose on the top, rack hose with the locking tab on bottom). Which way is correct and does it even matter?

    Edit: after thinking about this some more and reading some other posts, it looks like others have commented about the realoem diagram for these hoses being inaccurate. Either way, the only thing that would change is the direction of the flow of fluid though the cooler. And unless there is some one-way check valve in there, I donít think it would matter which way the fluid flowed.

    https://www.realoem.com/bmw/enUS/sho...27#32411094205
    Last edited by BostonJon; 01-09-2023 at 01:33 AM.

  2. #2
    Join Date
    Jan 2008
    Location
    Missouri
    Posts
    608
    My Cars
    '02 540i/6
    My be 540i is having power steering leaks as well, but I'm just replacing every hose, the reservoir, everything except the pump. FCP has a kit that I'm going to pick up for peace of mind.

  3. #3
    Join Date
    May 2018
    Location
    Austin, TX
    Posts
    701
    My Cars
    2003 540i | NSX | CB550
    I've had my PS hoses hooked up backwards to the cooler for a few years now. Doesn't seem to cause any issues so I'll just fix it next time I flush the fluid.

  4. #4
    Join Date
    Dec 2015
    Location
    Boston, MA
    Posts
    109
    My Cars
    2007 BMW 530xiT
    But which orientation is the correct one?

  5. #5
    Join Date
    Sep 2006
    Location
    NW suburban Chicago
    Posts
    15,840
    My Cars
    hiss by my window
    Reservoir hose goes on top.
    WRONG see post 21
    Last edited by ross1; 01-27-2023 at 02:51 PM.

    If you can leave two black stripes from the exit of one corner to the braking zone of the next, you have enough horsepower. - Mark Donohue

  6. #6
    Join Date
    Dec 2015
    Location
    Boston, MA
    Posts
    109
    My Cars
    2007 BMW 530xiT
    Thanks. How were you able to confirm this?

  7. #7
    Join Date
    Sep 2006
    Location
    NW suburban Chicago
    Posts
    15,840
    My Cars
    hiss by my window
    Because there are very few parts of this car I'm not familiar with and just installed the drivetrain into one this past weekend. Good enough?
    The real oem diagrams are often useful but not an assembly manual.
    As stated before the cooler couldn't care less which direction the oil flows.
    well this is embarrassing See post 21
    Last edited by ross1; 01-27-2023 at 02:52 PM.

    If you can leave two black stripes from the exit of one corner to the braking zone of the next, you have enough horsepower. - Mark Donohue

  8. #8
    Join Date
    Dec 2015
    Location
    Boston, MA
    Posts
    109
    My Cars
    2007 BMW 530xiT
    Quote Originally Posted by ross1 View Post
    Because there are very few parts of this car I'm not familiar with and just installed the drivetrain into one this past weekend. Good enough?
    The real oem diagrams are often useful but not an assembly manual.
    As stated before the cooler couldn't care less which direction the oil flows.
    Thanks. I wasnít challenging you, just trying to understand how/where you were able to confirm the orientation given the discrepancy between real OEM and what appears to be the actual orientation of the lines. I donít see why the flow direction would matter and I donít have any issues with the steering now other than the leaks, which seem to be pretty common.

  9. #9
    Join Date
    Sep 2006
    Location
    NW suburban Chicago
    Posts
    15,840
    My Cars
    hiss by my window
    The way these are put together that clamp swings to the outside. If putting them on without the radiator in place the tendency might be to reverse that(which results in switching positions)as there is more room to work on the inboard side without the radiator in place.
    Don't forget to replace the 0-rings too PN 17 21 1 742 636
    Last edited by ross1; 01-10-2023 at 02:01 PM.

    If you can leave two black stripes from the exit of one corner to the braking zone of the next, you have enough horsepower. - Mark Donohue

  10. #10
    Join Date
    Dec 2015
    Location
    Boston, MA
    Posts
    109
    My Cars
    2007 BMW 530xiT
    great point about the orientation of the clamp. Looking at the RealOEM diagram, the clamp is on the bottom hose and would need to swing inward (towards the radiator) - counterclockwise when looking from the front of the vehicle. as ross1 noted, this would potentially cause some space issues because of the radiator.

    however, if the clamp were on the bottom hose (as it seems to be in our cars), it would swing counterclockwise but away from the radiator and there would be plenty of room to work on the hoses.

  11. #11
    Join Date
    May 2009
    Location
    Greenville, SC USA
    Posts
    2,630
    My Cars
    e39 M5 e39 540i6 e83 e53
    Both my 540i and M5 have the reservoir hose on bottom. For whatever that's worth. Owned the M5 for 5 or 6 years and no issues, although I did replace the reservoir and hoses at some point if I remember correctly.

    I haven't driven the 540i long enough to have any history but no steering issues that I know of.

    First pic is the 2001 540i 6 speed, second 2 pics are the 2000 M5. Hope it helps. Hard to get good pics with the second air box in the way.

    IMG_20230111_190842720.jpg

    IMG_20230111_191119273.jpg

    IMG_20230111_191053569.jpg

  12. #12
    Join Date
    May 2009
    Location
    Greenville, SC USA
    Posts
    2,630
    My Cars
    e39 M5 e39 540i6 e83 e53
    Bentley manual pic pic shows the reservoir hose on top.
    Nothing else very helpful in the Bentley that I could find.

    I'm pretty sure the pictures on realoem and Bentley are inaccurate for hose to cooler orientation. There are even differences between the two.

    Reservoir hose on bottom final answer ��

    IMG_20230111_192318245.jpg
    Last edited by Auto Parts Guy; 01-11-2023 at 08:00 PM.

  13. #13
    Join Date
    Oct 2017
    Location
    Beaverton, Oregon, USA
    Posts
    1,690
    My Cars
    2001 E39 540i A, 207 k
    Quote Originally Posted by BostonJon View Post
    Hi, Everyone-

    I'm slowing tracking down the source of several power steering leaks. I had a leak at the bottom of the reservoir and replaced the reservoir along with the return hose (reservoir bottom to cooler) and this has fixed one leak. The other hose at the cooler (to the rack) is also leaking where the soft rubber part meets the metal flange (near the cooler).
    ....
    https://www.realoem.com/bmw/enUS/sho...27#32411094205
    To fix the leak, try to remove and replace the O-rings at the end of the hoses where they meet the flange, #11 in the diagram. There is also another hidden O-ring behind bolt #13 in the diagram.
    Replacing those O-rings fixed my leak. Replacing the hoses did not.

  14. #14
    Join Date
    Aug 2016
    Location
    Virginia,USA
    Posts
    2,979
    My Cars
    528i, 525iT, M5, x5 4.8
    The incorrect view of these hoses on REALOEM is a well know error. As Ross1 posted the correct orientation is Res to the top. Always replace the little O-rings! I will be doing this on my own M5 next week.

    Image of 6 banger hoses are the same. Big stem on TOP, little stem on bottom.
    Attached Images Attached Images
    Last edited by StephenVA; 01-12-2023 at 04:32 PM.
    Current Garage Highlights
    2005 X5 4.8is Le Mans Met Blue
    2003 525iT TiSilver
    2002 M5 TiSilver
    1998 528i KASCHMIRBEIGE METALLIC (301) (Goldie)

    Former Garage Highlights
    2004 325iTs (2x)
    1973 Pantera L
    1971 Dodge Dart Swinger "Lite Package"
    1970 Dodge Challenger T/A 340 Six Pack Alpine White
    1970 Dodge Challenger T/A 340 Six Pack GoManGo Green
    1969 Road Runner 383
    1968 Barracuda Formula S 340 Sea Foam Green

  15. #15
    Join Date
    Aug 2016
    Location
    Virginia,USA
    Posts
    2,979
    My Cars
    528i, 525iT, M5, x5 4.8
    Clean those engine bays!
    Attached Images Attached Images
    Last edited by StephenVA; 01-12-2023 at 04:38 PM.
    Current Garage Highlights
    2005 X5 4.8is Le Mans Met Blue
    2003 525iT TiSilver
    2002 M5 TiSilver
    1998 528i KASCHMIRBEIGE METALLIC (301) (Goldie)

    Former Garage Highlights
    2004 325iTs (2x)
    1973 Pantera L
    1971 Dodge Dart Swinger "Lite Package"
    1970 Dodge Challenger T/A 340 Six Pack Alpine White
    1970 Dodge Challenger T/A 340 Six Pack GoManGo Green
    1969 Road Runner 383
    1968 Barracuda Formula S 340 Sea Foam Green

  16. #16
    Join Date
    Sep 2006
    Location
    NW suburban Chicago
    Posts
    15,840
    My Cars
    hiss by my window
    Quote Originally Posted by StephenVA View Post
    The incorrect view of these hoses on REALOEM is a well know error. As Ross1 posted the correct orientation is Res to the top. Always replace the little O-rings! I will be doing this on my own M5 next week.

    Image of 6 banger hoses are the same. Big stem on TOP, little stem on bottom.
    Also, no O-ring needed for the clamp's bolt, it doesn't see any fluids.
    I can't believe the number of posts for this question.
    Last edited by ross1; 01-12-2023 at 05:51 PM.

    If you can leave two black stripes from the exit of one corner to the braking zone of the next, you have enough horsepower. - Mark Donohue

  17. #17
    Join Date
    May 2009
    Location
    Greenville, SC USA
    Posts
    2,630
    My Cars
    e39 M5 e39 540i6 e83 e53
    Quote Originally Posted by ross1 View Post
    Reservoir hose goes on top.
    Quote Originally Posted by StephenVA View Post
    The incorrect view of these hoses on REALOEM is a well know error. As Ross1 posted the correct orientation is Res to the top. Always replace the little O-rings! I will be doing this on my own M5 next week.

    Image of 6 banger hoses are the same. Big stem on TOP, little stem on bottom.
    ??? Realoem and Bentley show reservoir hose on top. But if it's wrong, then how does it go on ..top??

    The little stem on my cars IS the reservoir hose. Which is on bottom..

  18. #18
    Join Date
    Aug 2016
    Location
    Virginia,USA
    Posts
    2,979
    My Cars
    528i, 525iT, M5, x5 4.8
    I stand corrected, realoem for M5 shows the correct orientation
    years ago it showed the m5 ass backwards hence all the fights on the m5 forum over the issue
    Current Garage Highlights
    2005 X5 4.8is Le Mans Met Blue
    2003 525iT TiSilver
    2002 M5 TiSilver
    1998 528i KASCHMIRBEIGE METALLIC (301) (Goldie)

    Former Garage Highlights
    2004 325iTs (2x)
    1973 Pantera L
    1971 Dodge Dart Swinger "Lite Package"
    1970 Dodge Challenger T/A 340 Six Pack Alpine White
    1970 Dodge Challenger T/A 340 Six Pack GoManGo Green
    1969 Road Runner 383
    1968 Barracuda Formula S 340 Sea Foam Green

  19. #19
    Join Date
    May 2009
    Location
    Greenville, SC USA
    Posts
    2,630
    My Cars
    e39 M5 e39 540i6 e83 e53
    I looked at another random 2002 540i today and the reservoir hose was on bottom. Interesting nonetheless

  20. #20
    Join Date
    Mar 2018
    Location
    Milford, CT
    Posts
    444
    My Cars
    03 540iA M sport
    What PS fluid did you use?

  21. #21
    Join Date
    Sep 2006
    Location
    NW suburban Chicago
    Posts
    15,840
    My Cars
    hiss by my window
    Quote Originally Posted by Auto Parts Guy View Post
    ??? Realoem and Bentley show reservoir hose on top. But if it's wrong, then how does it go on ..top??

    The little stem on my cars IS the reservoir hose. Which is on bottom..
    Edit and apology to the misinformation I've been offering:
    I'll have a slice of humble pie to go with that crow, please.
    SO! Mr. Cocksure of himself had a look at his car today. Reservoir hose is on the bottom alright.
    Not sure what I was envisioning but I'd have bet(and lost) the farm on the image in my mind of the reservoir hose closer to the observer. Perhaps because I usually am doing these from underneath after a big engine out job. Sorry, I'm making excuses.
    Anyone that has reversed their set up on my account in the interest of being factory correct may feel free to administer a kick in my nads.
    Please disregard all of my oh so sure of myself insistence that the reservoir hose is on top, it is not.

    Functionally it doesn't matter, the oil cooler works the same regardless of flow direction.
    That is all
    Last edited by ross1; 01-27-2023 at 02:51 PM.

    If you can leave two black stripes from the exit of one corner to the braking zone of the next, you have enough horsepower. - Mark Donohue

Similar Threads

  1. e39 540 AC hoses to GM compressor and condenser
    By James39 in forum Engine Conversions
    Replies: 8
    Last Post: 07-19-2012, 10:10 AM
  2. E39 e39 540 pair of new, unused front Power Slot rotors
    By z0lt3c in forum Brake Kits, Rotors & Pads
    Replies: 3
    Last Post: 07-23-2007, 09:51 AM
  3. E39 Revhigh intake for E39 540
    By Boostedjuice in forum Engines, Performance Parts & Software
    Replies: 4
    Last Post: 07-20-2007, 08:56 PM
  4. E39 e39 540 pair of new, unused front Power Slot rotors
    By z0lt3c in forum Brake Kits, Rotors & Pads
    Replies: 2
    Last Post: 05-16-2007, 10:00 AM
  5. E39 GruppeM CAI FS !!! E39 540 use
    By Ken21 in forum Engines, Performance Parts & Software
    Replies: 2
    Last Post: 04-10-2007, 11:37 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
  •