PDA

View Full Version : Audible stuttering/tapping sound when idle and constant air out of vents?


Boxy
05-09-2011, 05:46 PM
Sorry if this has been addressed before, but I skimmed the forums and couldn't find mention of it.

I drive an 08 MZ3 GT hatch, and have noticed this tapping for a while now. I brought it to the dealership to ask and they said it was simply the air conditioning mechanism working, even when the AC was not turned on. How accurate is this to you guys? I haven't noticed anything else particularly strange about the car, but the tapping sound is kind of annoying. I don't believe it occurs until a period of time after starting the car.

On the mention of AC, I've always wondered why I can still feel air (hot or cold depending on the temperature knob setting) coming out of the vents when the airflow knob is set to "-", the pattern changes with which "-" setting is used so I'm guessing it's just outside air flowing through the vents? But why wouldn't all the vents be closed when turned off?

Help would be greatly appreciated :)
Jason
cwp_sedan
05-09-2011, 05:56 PM
I'm not sure about your first question, though I have a weird noise like that had slow idle speeds when I press the brakes. I have yet to figure out what it is.

It could just be the motor as they are known to be a little noisy.


As for the air, this is 100% normal. Fresh air comes in from outside and it has to go somewhere. You will find this happens when the dial is set left of the 12 o'clock position. If you press the recirc button while having the dial set to any of those positions as well, the air flow will stop.
Boxy
05-09-2011, 05:58 PM
D'oh, I never thought about seeing what the recirc button did to the effect. Thank you for clearing that up :)

Would I be able to go to a different dealership about the tapping noise? Would they be able to warranty service if needed? It doesn't sound like that noise is typical for air conditioning... >_>
cwp_sedan
05-09-2011, 06:03 PM
D'oh, I never thought about seeing what the recirc button did to the effect. Thank you for clearing that up :)

Would I be able to go to a different dealership about the tapping noise? Would they be able to warranty service if needed? It doesn't sound like that noise is typical for air conditioning... >_>

Absolutely. If one dealership can't fix your issue, definitely try another. Take a ride along with them and point out the noise. Show them how it makes the noise without the fan or A/C compressor running. Hopefully they can figure out what it is.