Clattering noise during warmup...

Discussion in '2012-2016 VW Passat TDI forum' started by New TDI, Dec 29, 2015.

  1. New TDI

    New TDI New Member

    Joined:
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    Car:
    2012 Passat TDI SEL Prem.
    Location:
    Minnesota
    Hi All,
    I've had my '12 Passat TDI for 3 previous MN winters and warmups have always been trouble free. This cold season, 60K miles now, I've noticed a rather loud clattering noise when lightly loading the engine during warmup. Starts up fine and sounds normal for starting cold, less than 45 deg. F. I generally idle just enough to ensure oil pressure comes up before I start moving, then proceed gingerly until the engine warms up. Prior to warmup, first and second gear engine sounds normal (no real engine load). Into third gear and higher when accelerating (light engine load) I hear a rather loud clattering noise synchronized with engine RPM. Noise will disappear if I let off the accelerator and reduce engine loading. Noise will continue to come back under load until the temperature gauge comes off the bottom (120 Deg F I think). Once engine has warmed past 130 degrees or so, things seem to sound and run normal. No change in mileage, not burning any crankcase oil, just had my 60K service and dealership says everything looks good, no codes etc.
    Has anyone experienced this? Some engines are temperamental when cold but this one was fine for 3 years so I'm worried something is wrong.... My best hypothesis is fuel starvation or bad injection timing when cold. Not based on any real knowledge or experience, more from lack of other ideas. The fact that everything clears up when the engine warms also makes me think the engine control unit may be getting false temperature information and thus behaving as though the engine has warmed up prior to when it really has.
    Would appreciate any advice. I would like to upload an audio clip but not sure how to do that on this forum...
     
  2. Vwman2015

    Vwman2015 Member

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    Car:
    Vw golf, mk5 2005 sdi, bkd engine
    Location:
    Clacton
    Well its always hard to diagnose on the Internet so going by what you say hmm. ...
    Clattering noise,sure it's not more of a clunking noise?

    Dual mass flywheel fail which results in load noise.

    Now noise when temp low till rises hmm.... again hard one but could be piston slap but this again would be slightly different noises like a groal or slap noise but you have to be really really unlucky at only 60k...

    So me thinks poss dmf issue
     
  3. Vwman2015

    Vwman2015 Member

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    The oil ain't low is it
     
  4. Vwman2015

    Vwman2015 Member

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    Car:
    Vw golf, mk5 2005 sdi, bkd engine
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    60k clattering hydraulic tappets but again really unlucky at that millage..


    Keep us updated
     
  5. New TDI

    New TDI New Member

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    2012 Passat TDI SEL Prem.
    Location:
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    Dual mass Flywheel? Does that apply to manual, automatic tranny or both? Mine's got the DSG Auto.

    Definitely not low on oil but don't know about oil pressure. No dummy lights or ODB2 codes.
     
  6. Vwman2015

    Vwman2015 Member

    Joined:
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    Car:
    Vw golf, mk5 2005 sdi, bkd engine
    Location:
    Clacton
    Apply to both, auto dsg has twin shaft and twin clutch so needs dmf to protect gearbox from vibrations.

    Also

    In my experience hydraulic tappets will not show any codes, the clattering noise on warm up is a sign.
    Worn tappets lose oil over night hence the sound...

    Worn dmf test,

    On start and stop pull off you will hear it mostly, drive the car to roughly 2500 revs then allow the car to slow to a halt listen
    To clunks or rattles and this will be almost be constant even if the engine is warm.

    Worn tappets,

    The noise will fade once the tappets have regained an oil supply.

    Your best bet would be to put a video on here for others to hear the noise and pass comment or to a garage for test run..
     
  7. New TDI

    New TDI New Member

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    Car:
    2012 Passat TDI SEL Prem.
    Location:
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    Thanks for the insights VWman2015...
    I don't think the DMF is the issue since there's no noise whatsoever when the engine coolant temperature exceeds about 130 or so, but something in the valve train is a good possibility. Worn tappets? Would you still suspect worn tappets if the noise only occurred under engine load when cold? I can start the engine cold and let it idle to warm up and would never hear the noise.
    Other ideas... Can't blame ignition timing with a diesel but injection timing and/or injection volume maybe? I do have it into the dealership for the second time. First time they said they could not reproduce the noise or failed to diagnose.
    BTW, I recorded an audio clip and then also created a video clip but neither file type are "uploadable" using the "Upload a File" button on this forum.... It seems the file types allowed for upload are limited.

    Thanks again for your ideas.
     
  8. New TDI

    New TDI New Member

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    2012 Passat TDI SEL Prem.
    Location:
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    Resolution!
    VW Dealer diagnosed a bad fuel injector. Since it was under warranty, they said it would be best to replace all 4. They replaced all 4 fuel injectors at no cost to me and it seems to have cured the problem. I've gone through 3 warm-up cycles since the repair and no noise or shuddering whatsoever under load. The symptoms were very repeatable before so I'm quite confident that the repair has been effective. I'll report back if anything changes.

    I assume the one cylinder was not getting sufficient fuel when the demand was the greatest (cold engine and under load). If the bad injector was incapable of delivering large doses of fuel, this would be consistent with the symptoms in my opinion.
     
  9. mike moses

    mike moses New Member

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    Car:
    12 passat, 03 golf, 03 jetta
    Location:
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    i have the identical symptoms on a 2012 Passat with 118K Did the injectors resolve the problem? If I was to write a description of what I'm dealing with it would read exact same as yours does.
    I was thinking lifters (tappets I guess you guys call them) but will have the injectors tested if that was your issue after all.
     
  10. New TDI

    New TDI New Member

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    Mike, I'm now very confident that the new injectors solved the rough/noisy warm up issue. I've gone through probably 50 cold warmup cycles and have not noticed anything unusual. I don't quite understand how the injectors can be tested but that's what the dealership claims they did. Also, not sure what a new set costs for parts & labor since I was just under the 60K mile limit and all was covered with the power train warranty. All in all, I'm quite happy with how my dealership took care of things.
    If you get a chance, report back how your diagnosis & repair goes.
     
  11. mike moses

    mike moses New Member

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    Ive owned a bunch of dodge diesels and the 03 and 04's would have injector issues on cold start ups after the trucks had sat. An injector shop would test all 6 for around $100 and you would spend $300ish replacing the bad one(s). Lots of guys would just throw down the 1800 at once to go another 10 years without cold start issues. I'll update on where I land with my diagnosis and treatment, but I'll def. look at injectors as one of the first things. Not sure if vagcom or maxidas will be able to provide any feedback on cylinder parameters?

    Appreciate your posting and reply
     
  12. New TDI

    New TDI New Member

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    Well, I've gone through another complete MN winter (2016-17). Ever since injector replacements last winter, I haven't noticed any warm up issues. Just glad they decided to fail prior to the 60K mile mark.....
     

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