rocco_ca

Me too love the car

poker838

OK

I'm pretty sure that howling noise when you get off the throttle is from your 2.0T engine. There's a turbo in there. When you get off the throttle, the turbo is still spinning and (I think) it's the Diverter Valve that dumps the excess boost from your turbo back into the Intake.

For modders, they actually purchase an aftermarket DV to magnify that sound.

tomashek

Trust me, it's not turbo. I know what you're refering to, I hear my turbo. As a matter of fact, that turbo sound is very cool. I like it.
My howling noise comes from the back of the car.

poker838

hm I hear a different one coming from the back that does not sound like what you're experiencing.

Mine only does that on cold starts - about 30 seconds after I hit a drive gear. All the B8 A4s that I have driven had it (mine was in the shop a lot ...)

keetu

I have an A5 and I hear the same noise howling sound when I take my foot of the brake and hit the accelerator. The noise diminishes after the car speeds up.

scancomputer

The noise you hear is the sound of the turbo booster that build up pressure in the tubes. When you depress the accelerator, the booster lets out the pressure through the exhaust system instead of feeding it into the engine. That´s the uhhh-squeek you hear.
Mine is 2.5TDI chipped to 230HP and it does it all the time.

keetu

Thank you for your response Scancomputer. My car doesn't have turbo boost, so I'm going to assume that this wouldn't apply to my car. If you have any more insightful info to share, please do so. Much appreciated.

scancomputer

if you could make a video and send me, maybe I will recognize the sound? I have a 2000 & 2004 A6 avant TDI and I begin to know these vehicles quite well.

tomashek

Just to update on this, I have 25k now and hear it all the time when temp goes below 0, so winter time.... some days more than others....
I brought this numerous times to dealer attn with no positive resolution, and it was blamed on characteristic of the car....
I have learned to live with it....
Summer time however, there is nothing, no howling! So this thing, whatever it is, is tied up to outside temp, big time.

kirstenkelly

Did anyone figure out anything else about this noise? I have a 2012 A4, 2.0L turbo and my car makes the same noise. It makes a howling noise that sounds like it's coming from the rear of the car, but only when it's very cold outside. It happens when I let off of the gas or press the clutch in, usually under 50 mph. Lately I have been starting to hear the noise at around 60 mph as well. The noise always goes away once the car warms up. I brought my car into the dealer and of course it was not making the sound once I brought it in.