Hello everyone,

First off let me say sorry to keep posting about noises coming from the engine compartment. But this one is very interesting as there are no other A8 forum posts about it. I realized the sound occurs both in park and drive, have not tried neutral yet. The noise only occurs at 1000-1300 rpm and last less than a second when accelerating. While in park it is difficult to replicate in the sense that you have to rev the engine within a certain range i.e. not a slow and gentle rpm raise nor a fast and rapid rpm raise, it is like the middle ground of the two and seems to be vibration based. Besides that difficultly it is also quieter and lasts a shorter period while in park. The sound is best described as being three quick taps or rasps. I honestly just think it is something loose on the exhaust or something loose in the engine compartment, as noted by other Audi model forum posts. I just curious to see what you all think it is or if the issue has occurred before. The video will be linked below. The first rattle occurs at 6-7 seconds, after that it occurs every time I accelerate from a stop or manage to get the rpm below 1000 while moving. Its also best heard on an iPhone or with headphones. I will try and go to a quieter area later today to get a better recording of the sound.

 

If you don't, then forget it. You should check the car for noises before you bought it since you're so meticulous about noises and stuff. I have the hooting noise every time I accelerate quickly at 20-30MPH when it hit 100k mile mark, I'm not going to spend $1000 to change fluids, program TCU and hope the noise goes away. I can live it with it since I don't accelerate abruptly @20-30mph often, I'm a smooth driver.

Cheers,

Louis

 

I can hear it but no idea what it is. It sounds like something light or plastic. I would get under it and put a wrench or screw driver on all the fasteners for any bracket or brace. Could also be one of the underbody panels moving around.

 

You can hear it inside. Only when the AC and radio is off. Even then it is still faint. Also when you can here it inside it originates from the passenger side, almost even the passenger foot well.

 

You can hear it inside. Only when the AC and radio is off. Even then it is still faint. Also when you can here it inside it originates from the passenger side, almost even the passenger foot well.

 

Little update. Did a cold drive this afternoon and found that the sound was non-existant. It only started to occur when the engine was almost at normal temp. So I am thinking something exhaust or attached component related. I don't think I have to worry about anything with the internals of the engine because the noise doesn't follow the rpm range when reving thankfully? Should be able to get it on a lift sometime late this week and investigate.

 

That will narrow it down some, you only need to concentrate around the engine, and long the exhaust.

I had a wicked heat shield rattle on my old Jetta Trek that took over a year of off and on looking/hitting/bending/cursing to track down. Good luck!

 

It almost sounds like a bad cat.