Weird noise coming from under the car

[VW_TDI_2014]

I’m not sure if anyone is actively on here anymore. However, I have a 2014 VW TDI SE Passat and more recently have been having this issue under my car. Whenever it has been running in the heat for sometime and I shut the car off I notice this loud vibrating noise from under the car. It happens for some short time then stops but I can’t figure out what it is. If anyone has any idea I would love to hear it cause Volkswagen wants to charge me a fortune just to diagnose the problem.

 

[06bluebeetletdi]

Are the cooling fans running? Mine (14 passat) runs the fans everytime I shut it off, if the outside air temp is over 72*. Maybe a failing fan is the cause of the vibration. My bug only runs the fans after i shut it off if I interrupt a regen.

 

[VW_TDI_2014]

Are the cooling fans running? Mine (14 passat) runs the fans everytime I shut it off, if the outside air temp is over 72*. Maybe a failing fan is the cause of the vibration. My bug only runs the fans after i shut it off if I interrupt a regen.

The fans are running when I shut it off. https://drive.google.com/file/d/1jzgH5F3A5-p2NDM5gQYox5jmlGFSQ1b5/view?usp=drivesdk
I attached a video showing the sound of that helps out better. The fans continue to run even once the noise has stopped though so I am not very sure it is just one of the fans.

 

[Lightflyer1]

Link requires access permissions.

 

[VW_TDI_2014]

Sorry try this one. https://drive.google.com/file/d/1jzgH5F3A5-p2NDM5gQYox5jmlGFSQ1b5/view?usp=drivesdk

 

[AverageAndy]

So mine has that same "clanking" although not sure if it is that loud as I have never tried to record it closely. This is on a previous post, but my theory is it is part of the cool-down after a regen cycle, maybe one that got interrupted?

If it turns out to be a problem that needs to be fixed, please let me know!

 

[VW_TDI_2014]

Thank you for the advice! I guess I should see what all works during the cool down cycle to get a better idea.

 

[06bluebeetletdi]

Fans sound like a regen, i’ve never noticed that noise with mine, I’ll have to check next time it decides to regen when I’m close to home/work. My commute is 90% highway, so it usually regens on the highway.

 

[VW_TDI_2014]

I have only noticed the noise when the car has just been turned off. I’m not sure if you will be able to hear it while on the highway unless I’m mistaken.

 

[AverageAndy]

My commute is 90% highway, so it usually regens on the highway.

I think he is referring to all of his regens being completed while underway on the highway, which is the most ideal way. If that is the case then he would not hear the clanking noise at shut down.

 

[06bluebeetletdi]

Yes, never heard it with mine. I’ll have to catch a regen at home/work. Im a she btw i wonder if it’s the beginning of a regen where the temperature goes from 500-600* cruising at the egt sensors up to 1000-1200*

 

[VW_TDI_2014]

Oh okay. What I would like to find out is what is causing is, because that noise doesn’t occur every time I turn off the car even after a long drive. Which is confusing cause even on a hot day when I drive for about a hour it sometimes does it and sometimes does not produce that sound.

 

[AverageAndy]

My apologies @06bluebeetletdi.

I don't hear the sound every trip, and most of mine are a 60+ mile round trip commute. I would guess most of my regens get completed during the drive (and a lower than normal mpg is evidence). This is what leads me to believe the clanking, when it does occur, is part of a regen interrupted.

 

[VW_TDI_2014]

Okay so now I have noticed the fan that typically cools the turbo is not running once the car is off. Any idea what could be causing that? I have no idea what fuse it would be if that’s the problem.

 

[scrambld]

Any chance something is caught in the fans housing or a bad (wobbling) fan? I can't see any part of a regen causing that racket?
Listened again. It certainly sounds like something hard bouncing inside an exhaust component....especially near the end, going from knocking to more of a tinny ping sound? Interesting.

 

[VW_TDI_2014]

At first I thought about that too. However I’m not sure If that theory was investigated more.