Hey everybody,

You may have seen my other thread, in which I am trying to diagnose a MAF code. The following video seemed worthy to post separately though, just because it is so odd. Perhaps this issue and the P115C MAF code from the other thread are linked.

Fortunately, I was able to capture a video of the symptoms this time. Any ideas what the sounds in this video are pointing to? Could it be exhaust back pressure? Fuel pressure? It sounds like something is being relieved at 0:23. As always, any thoughts or ideas to test are welcome! Note: all sounds in the video are from the car.

https://www.youtube.com/watch?v=swWe...ature=youtu.be

 

I hear a similar muted "clunk" after shutdown in my R56. I can't determine what it is. It seems to be coming from the right rear corner of the car. It clunks about 5 -8 times at intervals of about 20-30 seconds. It makes the noise whether the parking brake is on or off. Anyone have any suggestions? I don't think it sounds like an exhaust pipe cooling and contracting. I'm very light on brake usage. I thought it might be a purging of pressure in the fuel lines near the pump but it sounds more solid than that—as the sound of the parking brake handle being released after the button is depressed, and letting the handle fall to the bottom position; except that this sound is from the rear right quarter of the car.

 

I wonder if it is you're auxiliary water pump shutting off?

 

My noise is from the rear of the car.

 

Sorry, I was referring to the OPs noise.

 

Rear of the car could be the fuel tank. I believe the tank gets pressurized at some point, and the noises from the rear could be the tank reacting to that pressure. It could also be the exhaust contracting, because the metal expanded when it was heated up and it's cooling down now.

The "clunk" in the OP's video sounds more like a solenoid moving or some such. No idea what it could be, though.

 

My noise (and video) is also of the right rear quarters of the car. It sounds like we are facing similar issues.

It might be worth removing the rear seats to see if that's where the sound is coming from

 

I have the same noise as you describe coming from the rear after shut down. Not too worried about it and definitely not worried enough to take the rear seats out to find where the noise is coming from.

Kind of sound like if you were on a hill and had the parking brake on and the car was ever so slightly rolling and making the sound of the brakes giving into the weight of the car.

Mind you I'm not on a hill. Or the brake on. Just that funny sound makes me think of that scenario.

Anyway, your not alone. I'll stay tuned to see if you find the source.

 

Mine has made a noise as long as I've owned it. Same area you're talking about. I always figured it was some sort of pressure relief system having to do with fuel tank or pump.

 

I get the same sound, kinda scared me at first I figured it was something with the fuel tank depressurizing. I does sound different.

 

I have also heard a electronic solenoid switching sound in the rear somewhere near the bottom of gas tank, but doesn't sound anything like yours.