After turning off the car and taking the keys out of the ignition I hear this higher pitched whistle sound for just a second. This doesn't happen every time I go for a drive and turn off the car (actually it's only happened twice so far). My girlfriend's brother also has an '05 MCS that exhibits the same whistle. Like I said, this doesn't happen all the time. I just tried to duplicate the sound and could not, so it appears random.

I'm not that good looking, so what could it be?

Thanks, guys.

 

Could be the fuel tank vent solenoid venting.

 

make sure the vacuum hose on the fuel pressure regulator is on

 

Where is that located on the car and I'll go take a look.

Thanks.

 

on the bottom of the fuel pressure regulator on the fuel rail

its a small black vacuum line that hooks to the nipple of the regulator

 

Checked. All is good! Maybe it's the back-to-back bottles of Chevron w/ Techron I added the last two times I filled up.

 

The car is whistling 'cuz it's happy? "Yum, yum. May I have another Techron, sir?"

 

It happens to me too, it almost sounds as if somthing is depressurizing and its audiable from inside the car?

 

Yep. That's what it sounds like to me too. And it's still doing it FYI. Maybe its the 90+ degree temperatures since Summer is here.

 

Any one else care to chime in?

 

Is the ac on when you turn off the engine?

I have this happening on my 96 Passat but my 06 Mini is just fine.

It was related to a pressure relief valve partly clogged

 

Nope. I've even tried it with the auto climate control on/off. Now that it hasn't been terribly hot and muggy I've noticed it's not nearly as loud.

 

Do you know what general area the noise comes from?

My car will sometimes make a "whirrrrrr" noise immediately after shutting it off and pulling the key out of the ignition. It only seemed to do this when Auto A/C was on, or if the recirculate mode was on.

I dug around, and found that a flap in the ventilation system moves (probably the fresh air flap?) the same time this noise happens. And it seems loudest on the passenger side, near the front of the vehicle.

 

The deflating balloon/pressure release noise sounds like it's going from the front passenger side of the car, just behind the engine. The sound only lasts a few seconds, so by the time I run around to hear exactly where it's coming from, it's too late. I even tried to pull into the garage, put the car in neutral, open the hood, turn off the car and run around to engine bay to listen.

 

Sounds to me like it might be the refrigerant (A/C) pressurizing or something. My MCS does not do this, but my other vehicles do this after driving w/ the A/C on. The hotter the day, the longer it "hisses" for.

Try running w/o the A/C on (even better w/ the whole auto a/c system shut down), and see if your car hisses at you after a drive.

 

i've got an 08 and my car makes the same noise you're describing when i shut it off....

 

I think it's the supercharger. Whether it's somehow depressurizing or coasting to a stop, you can hear it because the engine is off. Anyone else's thoughts on this?

 

Well it makes the sound regardless if the whole climate control is turned on or off.

 

Really? Sorta sounds like a balloon emptying out air combined with a slight, subtle bit of "fart"?

 

yeah, i might even go so far as to say its "the squeaker" kind of fart...like the fart fat bastard makes at the end of austin powers when he says "sorry, i farted"....

 

That's it exactly!

 

 

Is there any chance you could somehow take a video clip of this noise and post it on youtube or something?

 

i guess i can try tonight...idunno bought the op

 

I'll see what I can dig-up. Would hate to record it with my aged cell phone, but if need be.