For a month or two, I've been unable to get any cold air from the AC in my 2005 S4. But no other symptoms. Since it's been fairly cool out, I haven't been in a hurry to bring it in to be fixed. (That, and $!) Several days ago, I noticed that the climate control was stuck in 'ECON' mode and wouldn't go out of 'ECON' / economy mode (this was the first time that had happened). So, I just left the climate control totally turned off and went out to lunch with my girl - about 20 miles total.

Just as we were returning - I heard an AWFUL, AWFUL clattering / rattle noise .. it was such a nasty noise that at first I was convinced it was not coming from my car. But sadly, it was. No engine lights, no other oddness or warnings - and (other than the noise!) the car was running fine and totally responsive. With the climate control totally OFF, I drove the remaining mile or so to my house. The noise continued even with the climate control completely turned off.

Here is the noise:

Nasty Car Noise - YouTube

I shut it off and have not driven it since, except to back it out of the driveway for the tow truck this morning (and the engine didn't feel right, either.) I had it towed to the shop because there's just no way I'm driving a car making that noise. Also, there were a couple metal shavings and a small ball bearing under the car when I rolled it out.

My two questions for you experts:

1. WHAT THE FOCK, in the name of all that is Holy, is that noise?
2. Since I know the nose is coming off for this one, what else should I do preventatively while the car is in service position? It's an '05 S4 with about 58k miles.

Thanks guys,
-Anthony

 

To me it sounds like its an accessory running off of your engine. Did the noise get louder when your rpms got higher or was it constant? The only really good way is to open it up and take a look for anything out of the ordinary. Depending on the mileage im sure the snub mount needs replacing.

 

Based on what Im dealing with this is your compressor that failled and broke the drive shaft that runs it!... as far as I know it is designed to do this when the compressor fails...The compressor is located on the back drivers side of the engine and is powered by a shaft from the front of motor.

THIS IS A RATHER BIG JOB. requires the front bumper and motor mount to be removed along with quite a bit more to get to the compressor...from what I have read anyway.

I hope this helps other!

***note: if your ac compressor is designed to protect itself if the system is low...it your system is "stuck in econ" then it is most likely the compressor protecting itself from damage