Clunking rattling noise on 1 out of 10 startups

[droman81]

Getting a clunky noise every so often when I start my 04 zhp. If I give a little gas it stops. Sounds like it's coming from down low nearly underneath me. Loose heat shield on exhaust? Vanos? I will try and capture some audio. Any thoughts?


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[BMWCurves]

Hard to tell without video to understand where exactly it's coming from and what it sounds like.

[droman81]

Hard to tell without video to understand where exactly it's coming from and what it sounds like.

Understandable. I'm going to start recording every time I start the car so I can catch it when it happens.


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[droman81]

[https://vimeo.com/227092213/URL]
Ok, I think I got it uploaded. This was on second start up this morning holding phone right under driver side seat.


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[droman81]

[https://vimeo.com/227092213/URL]
Ok, I think I got it uploaded. This was on second start up this morning holding phone right under driver side seat.


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Uploaded incorrectly, will try again


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[droman81]

https://vimeo.com/227092213


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[slater]

weird. sounds like DMF. if you keep the clutch depressed, does it happen?

[droman81]

weird. sounds like DMF. if you keep the clutch depressed, does it happen?

That was no clutch, idling in neutral. I gave it a little gas and it stops. Haven't had a chance to try much else.


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[droman81]

weird. sounds like DMF. if you keep the clutch depressed, does it happen?

My girlfriends dad has a couple of classic corvettes and he thought it sounded like a loose exhaust heat shield.


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[BMWCurves]

My girlfriends dad has a couple of classic corvettes and he thought it sounded like a loose exhaust heat shield.


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Like the driveshaft is knocking against it?

[slater]

That was no clutch, idling in neutral. I gave it a little gas and it stops. Haven't had a chance to try much else.


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try holding the clutch in after startup and see (er, hear ;)) what happens.

[danewilson77]

Damn. That sounds horrid. I was initially going to say maybe exhaust/bracketing but the "1 out of 10" statement is throwing me for a loop.

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[droman81]

Damn. That sounds horrid. I was initially going to say maybe exhaust/bracketing but the "1 out of 10" statement is throwing me for a loop.

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It does sound somewhat similar to some videos of failing DMFs that I watched. Haven't had a chance to play with the clutch while it's happening yet.


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[droman81]

try holding the clutch in after startup and see (er, hear ;)) what happens.

Update: 2nd start up, noise started. Engaged the clutch and it stopped, let out and it started again. DMF going out?


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[slater]

Update: 2nd start up, noise started. Engaged the clutch and it stopped, let out and it started again. DMF going out?

sounds like it...

do you have any vibration on decel at highway speeds? this is where i was noticing vibration from my dying DMF.

[droman81]

sounds like it...

do you have any vibration on decel at highway speeds? this is where i was noticing vibration from my dying DMF.

Don't think so, everything else seems smooth. Did you end up replacing yours? If so did you stick with the dual mass?


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[slater]

Don't think so, everything else seems smooth. Did you end up replacing yours? If so did you stick with the dual mass?

haven't replaced it yet, but i have a valeo/LUK SMF conversion kit on the shelf - it will go in when i swap the drivetrain into my Touring. looking forward to that!