Alright so the other day i turn car on start for a drive alls fine and fine. Then i hear somehting. turn radio off and listen. There is a deep humming noise coming form the middle of the car/engine bay. maybe a shade towards the passanger side but that may just be because im on drives side. Any ways the noise doesnt exist untill like 35 mph. After that i start to hear it and as my speed increses so doent the speed of the humming and the pitch rises also. Right away i thought it was passanger side turbo gone by by but after driving around with this happening i have noticed that i can keep the car under 2800 RPMs and get up to 6th gear it it will still doo the noise with out and turbo spooling or anything.

If i was to try and make this noise my self i would turn on a house fan and put another plastic object right by the edge of the blade and let them barley hit..... I looked at the front fans on the engine all seem to be clearing everything ok and nothing stuck in them... On another note i also took the car for a 600 mile trip to upstate new york and back with this problem and had no issues. All the performance and eveyrhting is still there with the car. Gas mileage is still fine.

As for tires. That shouldnt bee the issue either because mine were rotated and balanced just over a month ago.... Any1 got any ideas???
IDK what a timing belt problem sounds like to an S4 soo possibly???

 

Anyone???
I dnt wont to make this sound bad but it does sound like one of the turbos - considering u said it sounded like a fan a bit?
Becasue u said it hasnt effected performance yet, it might be the start of the turbo (either compressor or turbine blades starting to rub on the inside of the turbo) losing effieceny but is still creating boost
How many miles on u S4?
Any way good luck and keep us posted
Cheers

 

wheel bearing with out a doubt its a classic sound

 

^^^
2nd. I currently have bad wheel bearing too. About a $200 repair. It's safe to drive on it, it's just incredibly irritating.

 

Ahhh touche thanks fellas. yea i actually got a friend that had his replaced on his 99 A4 for just under $100 a wheel. But im sure cause its the S ill get Effed in the A.

 

its not a good idea to keep using the car because it will damage the ABS sensor it enough wobble goes through the unstable wheel (advice only"