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Sudden appearance of rattling sound on engine start

Discussion in '4 Series' started by sivanes_81, May 31, 2017.

  1. sivanes_81

    sivanes_81 New Member

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    Hi there. Im pretty new to this forum and I recently joined due to a problem that I suddenly encountered which required my poor baby to be hauled onto a flatbed trailer and shuttled off to Auto Bavaria JB.
    I own a 2014 BMW 428i M-Sport, bought brand new from Quill Automobile in KL but has been serviced regularly at Auto Bavaria JB. I do quite a bit of running with the car as its my daily driver and have clocked 135,000km thus far. I recently sent in my car for regular oil change, inspection and rear brake disc and pad change and received my car on Friday , the 26th of May. Initialy I heard a very faint rattling on revving the Engine beyond 5000rpm which quietened at low RPM. I clocked in about 600km since collecting the car. Suddenly on Sunday, barely 3 days after leaving the service centre, the rattle got soo loud, almost suddenly increased in intensity and worsened with acceleration. The rattle was present even at idle and seemed to come from the engine bay. The noise sounded like stones shaken in an aluminium can and affected the idling of the car. I immediately shut the car off fearing the worse and got it towed to BMW. I was informed by the service advisor today that the problem most probably is due to the oil pump but I am quite sceptical as an impending oil pump failure should have showed up on their diagnostic when the car was in for is regular checkup a few days back. When asked , he said this a mechanical issue , therefore it was not picked up by the diagnostics. Then again, arent there sensors to pick up impending failures of such critical parts which if ignored could lead to catastrophic engine damage?
    I would really appreciate any and all input... My heart bleeds at the moment for the fate of my poor baby.... All alone in the dark chasms of Auto Bavaria's workshop
     
  2. jarance

    jarance Founding Member

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    Have you ever consider to open the bonnet to check the source of the sound?
     
  3. sivanes_81

    sivanes_81 New Member

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    Well, today they got back to me saying its an engine failure.
     
  4. jarance

    jarance Founding Member

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    Wow.. Sorry to hear this.
     
  5. gendong

    gendong Moderator
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    woowww..... sorry to hear that bro. hope they'll replace the engine as ur ride is still under warranty... heck was brand new off the showroom!!
     
  6. kevin1982my

    kevin1982my Club Guest

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    If the oil pressure is still within tolerance, i doubt the sensors will pick it up, even though the rotor is rattling like crazy inside the stator.

    Industrial machines sometimes have broadband vibration sensors attached to it. By analysing the frequency content of the vibration and how it changes over time, failures can be foretold. Eg: Previously the machine was quiet at 5Hz range and now you have a noise that got progressively louder at 5 hz range over past 3 weeks = something is loose and may be failing soon.With experience, you can even tell which bearing/shaft based on how the frequency peak changes with RPM/load/etc.

    Unfortunately. Such analysis are not typically done on cars so I believe its the reason why it was not pick up.

    Anyway, there is a silver lining here. If they change the engine for you, then you would have a new engine for your car.

    Not sure about the warranty TnCs for BMW nowadays. If it is unlimited millege and you service your ride at BMW all the time, then you should be golden.
     
  7. jarance

    jarance Founding Member

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    For industry, we use vibration monitore to measure peak-to-peak, velocity and acceleartion.

    By looking at the vibration spectrum, we can analyse the condition of bearing and moving parts.

    However, this is pratical at a fix speed.
     
  8. jarance

    jarance Founding Member

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    This picture show the spectrum of a big rotating machine using a portable vibration monitore.
     

    Attached Files:

    gendong likes this.
  9. kevin1982my

    kevin1982my Club Guest

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    Nice portable FFT unit you have there.

    The ones I have seen and use is like this. Better represent changes over a larger time interval.

    https://static1.squarespace.com/static/5238652fe4b00c5c300f33a0/53042386e4b0528766bfca55/530423eee4b00674c069e895/1392780439656/time-frequency++2+blur.jpg

    Anyhow, let us not get carried away with this.

    Did the thread starter get a new engine? Engine rattling sound ( stone in a can type) can be caused by another thing if its not oil pump. Crankshaft bearings. Rod knock!!
     
  10. sivanes_81

    sivanes_81 New Member

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    Hi there. thank you so much for the feedback. Well, it was a total engine failure due to the fuel pump but BMW Malaysia has declined to offer the good will warranty as there were delays in the service intervals. Instead they offered me a 30% discount on the repair which still amounts to RM18,000. Sigh...
     
  11. gendong

    gendong Moderator
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    Ouch..... sorry to hear that bro.
     
  12. kevin1982my

    kevin1982my Club Guest

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    So sorry to hear that bro.

    You mean fuel pump or oil pump? Doubt fuel pump can cause complete engine failure like that.

    Just curious buddy, how bad are the gaps in servicing?
     

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