cellis1

Hi, would appreciate any advice/opinion on a noise when driving A6 when pressing accelerator? Automatic gearbox.
I would describe it as a humming/hissing noise almost like it's coming through dash or over gear box - its constant when pressing and holding accelerator but once foot is removed it goes.
Interestingly when switching from drive to sport mode, the noise pauses for that small split second.
Secondly, I am not sure if linked but when leaving drive way for example and having to lock hard left or right I can hear a grind for a few seconds and then leaves.

Thanks in advance.

georgeb944

It's the sound of money leaving your bank account.

Take it to your Audi independent shop and ask their opinion. Since we can't hear the noise, it's going to be difficult at best to diagnose...

EuroPartShop!

While I can't diagnose the problem definitively without inspecting the car myself, I can offer some possibilities based on the symptoms you've described. A hissing noise when accelerating could indicate an exhaust leak. This would typically be more pronounced under load (when pressing the accelerator) and may change slightly when switching driving modes due to differences in engine behavior. Since the noise seems to be related to acceleration and changes when switching between drive and sport modes, there could be an issue with the transmission or related components. It might be worth checking the transmission fluid level and condition, as well as having a mechanic inspect the transmission for any signs of wear or damage.

A vacuum leak can also cause hissing noises, particularly when under load. This could be related to a hose or gasket somewhere in the engine compartment. A thorough inspection of the vacuum system may be necessary to identify and fix any leaks. Similar to a vacuum leak, an intake air leak could produce a hissing noise when accelerating. Check the intake manifold, hoses, and connections for any signs of damage or leaks.
T
If your Audi A6 is equipped with a turbocharger, a hissing noise could indicate a problem with the turbo or associated components. Issues such as a leaking wastegate or damaged turbo inlet could cause a hissing noise under acceleration. Regardless of the potential cause, it's advisable to have the car inspected by a qualified mechanic or Audi dealership as soon as possible to diagnose and address the issue before it potentially worsens. Ignoring strange noises in a vehicle can sometimes lead to more extensive and expensive repairs down the line.