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W210 320CDI Sudden Plume of Acrid Smoke... and all good?

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by Irresistance, Sep 10, 2011.

  1. Irresistance

    Irresistance Senior Member

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    Joined:
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    Location:
    Gdansk, Poland
    Your Mercedes:
    1988 W126 420SE, 2006 W209 200K & 1999 S210 320CDI
    Hello,

    Jus a quick question and/or story on what happened to me today. I was finally in Germany able to give the car some speed, and after about, oh, 40 minutes of 130-180 KM/h driving (avg. of about 160?) I saw my car belch out the most disgusting, bluey-grey near-opaque smoke from the exhaust. The car seemed to marginally lose a bit of power for really a few seconds only, and after that - nothing. In fact, it seems, the car runs BETTER now, stopped (gently) vibrating in idle (while in D) and seems more quiet now.

    Now - about 5000KM ago, I put in diesel injector cleaner, and went on a long trip to Italy. I am fairly sure that sometime towards the end of these 5000KM, something similar has occured, although the plume seemed to be less. At the time, I gave it the benefit of the doubt, and assumed it was someone else. Now I am fairly sure that was another such event.

    So - my THEORY is that the driving fast has "uncrusted" some crap stuck in the engine/cylinders, and that plume was simply that crap being burned away. This is supported by these observations:

    - The car seems to run BETTER now
    - Diesel Injector cleaner has been applied first time after... oh... 50K KM? (it just ran very well all the time, but I forced myself to add it, finally)
    - Streess/higher RPM (up to 3600RPM) which would shake things up
    - Aside of the plume, NOTHING else is wrong - no limp home mode, no smoking, no smell inside, the engine sounds like new
    - Because the car kept on going (virtually without a hitch), it is fairly reasonable to assume this is a single-cylinder event so to speak

    Does anyone have a better idea? Of course I am going to go check it out but as an unfortunate circumstance I also managed to incapacitate my hood-opening-cable a couple weeks ago so until I visit my mechanic on WED, I cant even properly open the hood ;)

    All I can add is that the car runs very well, I've had it for over 2 years now, done 120K with it, maintain it by the book with all filter/fluid changes as dictated from Stuttgart with MB originals (yes, the mechanics always think I am nuts)

    Thanks and Take Care :)

    W
     
  2. television

    television Always remembered RIP

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    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    Yes it does sound as though it blew some crap out of the manifolds and burnt it.
     
  3. Alex Crow

    Alex Crow Senior Member

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    Your Mercedes:
    W169, W124, w202, W203, KTM 250 EXC, VW T25 camper and a Polo in a pear tree
    quite likely crud going through, yes.

    not from cylinders though - it would be the build up from inside the inlet manifold, EGR and PCV products.
     
  4. OP
    Irresistance

    Irresistance Senior Member

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    Your Mercedes:
    1988 W126 420SE, 2006 W209 200K & 1999 S210 320CDI
    Thank you, case closed. Still will let an indie take a look... in general, would you advise a manifold reconditioning? I have heard some people do it and/or replace the plastic flaps with new (metal?) ones... is it worth it, from a longevity point of view...?
     
  5. television

    television Always remembered RIP

    Messages:
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    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    It would appear that it has cleaned itself out, I would just leave it, you have no warnings up
     
  6. Alex Crow

    Alex Crow Senior Member

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    Your Mercedes:
    W169, W124, w202, W203, KTM 250 EXC, VW T25 camper and a Polo in a pear tree
    as malcolm, probably no real need to get involved if all running OK.
     
  7. dieselman

    dieselman Senior Member

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    Your Mercedes:
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    I suspect the Cat has coughed up a furball...
     

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