I have a 2004 A6 2.7T. I have just started noticing a pretty decent vibration on the front end of the car and slightly in the steering wheel only when I turn on the A/C and more precisely when the compressor is on. Putting the HVAC in Econ mode makes the vibration go away as does turning off the air. The vibration is present when parked, in neutral and driving. You can see the vibration when I'm sitting behind another vehicle with the headlights on. Any idea what would be causing this?

I'm unsure if it's related, but I've also noticed what sounds like a VERY loud fan that's been kicking on when it's 90 or warmer out.

Any insight would be greatly appreciated.

Thanks!

 

Hmm.... the only thing I can think of is that the increased load is causing something to rattle when the A/C is on. Maybe check the pulleys/belts? As for the absence of vibration with no air, I am not sure. If you don't know what you are doing, I would advise taking it into the shop. With so many possibilities, it's hard to tell without seeing it.

 

On my 1998 A6 the bracket that hold the AC compressor cracked and a bolt broke, this caused a loud rattle and shook the car. I had to have the bracket replaced and the broken bolt removed. Not sure if this is your issue or not.

 

I'll check that bracket out. And of course if I can't find or determine what's going on I'll take it to the shop, but that's the beauty of asking all of my fellow enthusiasts. Just trying to pull on the collective expertise here.

 

Please post what you find out, I am curious what your problem turns out to be.

 

I'm curious as well. My guess is broken bracket, bad pulley/bearing or maybe a out of balance/broken fan blade for the a/c fan. But I have not f-ing ideal

 

I think you covered it, also.... real machanics have a few tricks for listening to running engine parts..maybe someone can suggest how they do this without buying that doctors tool that does it.

 

You use a long screwdriver.

 

Apparently I did a super bad job of spotting this when I looked earlier.

I found this fan with it broken off from the bracket.

Now the problem is that I need to identify what parts I need and where to get them. I don't have a Bently Manual, so if anyone would be so kind as to look up the part numbers for the fan and the bracket, that would be awesome.

I'm also open to suggestions on where to purchase replacement parts.

Thanks all!

 

Alright, I still don't have part numbers, but it looks like I need #11, "Upper Support" and #6, "Fan Assy" or should it be #1, "Fan and Motor 2.7L".

Does that check with everyone? Also, any idea where I could get these other than:

http://www.audiwholesaleparts.com/

I'll go with them if I can't find anyone else, but $213 and $65 still seems a little steep.

Thanks.