Humming A8L
 

Hello all
I wish I would have read through this forum before I made my purchase (guess what kind of '04 A8 do I have?)
Too late for that
I would like to find out anyone's opinion about a humming noise that my car has developed in the last 3 days.
I had Blizzaks installed on it 2 months ago so obviously there is a little more noise coming from the tires. 3 days ago I started hearing a constant humming that cannot be blamed on the snow tires anymore.
To describe it best, past 30MPH it sounds like a truck with OFFROAD STUDDED tires. It is not the engine because I have had the car coasting downhill with the engine off and it is just as loud. Transmission is acting normal. No vibrations or steering movement that would denote a bad tire.
Striving to be a DIY guy and not wanting to pay $125/hr. I had the car suspended in the air, did not find anything loose or broken, ran the car in drive at 5-10 MPH but didn't dare go full throttle while on the jack stands. Could not hear much because I had noone to step on it while I was out of the car.
Any advice on what to check or ideas ?
Any input would be appreciated
Thanks

Scary thought : Last time I heard that noise I had to swap the rear end in my Camaro.

It could possibly be a wheel bearing. While you are driving and hearing this humming noise try turning the steering wheel left and then right to see if you hear a change in the humming noise. If you hear the humming while turning one direction but not the other then that is further evidence to it possibly being a wheel bearing. For example if while turning your steering wheel to the left the noise is louder/more noticeable then that would indicate a wheel bearing issue with the front right wheel as that is the outer wheel where more pressure is exerted when turning to the left. I had a wheel bearing go on an Acura Legend and it sounded like "Tire noise" only quit a bit louder. I also did notice a change in the noise as I would turn the wheel from one direction to the other.

Good luck

cheap (but, labor intensive) fix to try... pull the rotors and lube the pad shims. costs almost nothing but the time and effort. may solve the hum.

A8L humming, scalloping,vibrating and more
 

The car has been humming tremendously and is very unpleasant and loud. ALL the four tires are scalloping on BOTH edges, outside and inside. Have performed alignment, tire rotation and does not help. Additionally the steering wheel feels like the wheels are rotating around rust. When you turn the steering wheel completely to any side there is a different loud humming and vibration. Have other problems too, but hope to solve these first.

2006 A8L, 32K, 6K on new tires.

Any help, ideas please!!!1

OK, those symptoms all suggest possibly wheel bearings, to me. If it were a '70's era (am I telling my age?) Fordsmobile, Pontillac, Lincoluic, or Dodgerolet I'd say bushings. IDK if VAG's come with DIYable bushings... Or, bushings at all, for that matter. Scalloping on the inside or out suggest toe-in or -out, depending on which side its on. Both kinda say that the wheel is going both ways. Coupled with the humming... SOMEthing is rubbing. Carnack-the-magnifixient predicts wheel bearings.

Any REAL mechanics wanna weigh in on my thought process? Confirmation, or, set me straight?

I'd also say: Go back to whoever did your alignment and punch them in tha throat for not diagnosing your problem!!!

Another thought occurs... Did you get the correct-sized winter tires, when you swapped in the blizzaks?

Bearing

Front wheel bearings it was
Thanks to everyone for the input

Problem solved
 

They updated the torsen differential fluid, and took to shave the tires and the noise is gone.
Not every dealer/mechanic knows this solution.