I have about 3K on my 2010 Premium Plus Sport Package 6spd a4. Around 2k I noticed sitting at idle in a parking spot this tack welding noise coming from underneath the car. It just sounds like something is getting tasered underneath my car. It would happen in half second jolts. I heard the noise with the e-brake and without the e-brake, w A/c on and w/o, etc. Only way I found out obviously was when my window was down. I don't see any leaks or warnings lights. Any suggestions to what it might be? Thanks in advance.

 

It is apparently normal for the B8s. Several threads have discussed this already on audizine. Something to do with metal cooling when the car is idle and not moving.

 

Thanks, I'll go search for the post on audizine.

 

I have heard a sizzle sound from underneath my car. It is from the AC condensation dripping onto a hot surface. I don't know if that is the sound you heard, but it is a common sound for the B8

 

It's definitely not from the A/C I have heard it on a cold day and when I haven't turned on the a/c at all during a drive or idle. I know what sizzle noise your talking about, but it's definitely different.
Thanks for your input!