AFrancis

So,
I had my serpentine belt replaced last weekend on the 4.2 at 106,000 miles. i didnt take it to an audi stealership but did go to a Audi mechanic. After a couple days, i noticed a humming noise coming from under the hood. The car doesnt vibrate, doesnt have rough idle, doesnt make any grinding noises, and the humming noise goes away when in park or idle. Only time i hear humming is when i accelerate in speed. I do live in michigan and its been 10 degrees all week.

I am assuming the belt is on too tight? I have no clue other than that.

raj99

it could be the idler pulley that the belt goes on as well. perhaps a bearing issue.

AFrancis

I would of heard the same noise before i replaced the serpentine belt if so, but this started happening after i replaced the belt.

raj99

perhaps you would, or knowing my luck when I replace something, something else breaks 'coincidentally' at the same time

Regardless, try the belt first, but just wanted to throw another option out there.

AFrancis

exactly why i made this post, needed more views on this. Thanks always

Medic1

Can you look in with a flashlight and confirm that it is correctly seated on all of the pulleys?

AFrancis

I see you mentioned bearing issue here. You were correct! Turned out to be passenger side wheel bearing. Thanks to these Michigan Roads, Just from this winters pot holes alone, ive had 3 flats (Continental Extreme Contact DWS) , abs sensor, and now wheel bearing. anyways

Thanks to those that helped

raj99

Glad you found the cause, bearings tend to go in harsh weather

Btw I'm getting a set of continental DWS, how did you like them?

AFrancis

I have the P245/40/ZR18 size which are low profiled. Rated over pirelli all season tires. Im not sure where you live, but in michigan weve had 8+ inches of snow at a time, and they are beasts. I never slipped once, as pick ups and jeeps were spinning out around me. The wear is good also, my rear ones have been on for 40,000 miles and still look new. But because of Michigan terrible roads, and pot holes the size of craters, these low pros pop easy and get bumbpy, but thats to be expected with all low profile tires ofcourse. Also they make barely any noise, cabin is still very quite.

AFrancis

DWS= Dry, Wet, Snow. I believe they are best for snow and wet weather. But yeah theyre great tires, you cant go wrong with them. They look really good too.