I did a couple of searches, and cannot find this problem on a 2015 F56. In warm weather, with the Air conditioner running, I get a whistle that sounds like it is coming from the windows. The car does not have to be moving. If I lean on the window, with just a little pressure, the whistle stops. I can also stop the sound by putting the air conditioner in recycle air mode. Therefore, I am confident it is caused by pressure in the cabin. My door seals are in good shape. I did clean them off thinking that maybe they had build up. I thought maybe it was a cabin filter issue, but it looks clean, and a dirty filter would let in less air, correct? So I am stumped, does anyone have any advice for me?

 

In for answers. my wife's f56 does the same thing.

 

My 2015 did it occasionally too, I would hit the up buttons for the power windows after I close the doors, I could hear them "snug up" and that would eliminate the whistle. I think it has to do with the indexing of the windows when the doors are open and closed. Could be something the dealership could do if you wanted to bring it in.

 

You are right in that it is cabin air pressure. What is going on is with the A/C running and bringing in outside air -- instead of just recirculating cabin air -- air pressure in the cabin is building up and leaking out past a window seal.

There should be -- I have seen this with other cars -- I have some pics but the pics don't really show that much detail -- a vent or two located at the very back of the cabin that lets air pressure and air flow from the cabin to the outside of the car. These vents to the outside are located so they allow air to flow into what would be a low pressure area of the rear of the car when the car is moving forward. The low pressure helps the positive air pressure in the cabin force open the flaps that normally are closed and seal the cabin against air coming in through these vents. (This to prevent exhaust gas from getting into the cabin if the car is sitting still.)

(With my Boxster a vent was located on either side of the rear trunk and vented out into a space between the rear trunk wall and the rear fender this space hidden under the rear bumper cover. But the area into which the vents were located was subject to low pressure when the car was moving.)

Based on my familiarity with these vent flaps of my Boxster -- they are most ingenious yet I can't believe only Porsche has this knowledge -- I'm surprised that the cabin develops positive air pressure to the point air is forced out the past a marginal window seal.

Has the car had any body work at the rear of the car?

What can you do?

With some cars -- not sure if yours is one -- when a door handle is pulled the side glass can drop a fraction of an inch. Then the glass remains down if the door is opened. When the door is closed the window goes back up.

Generally if this feature is present or the window offers a one touch down or one touch up operation there is a reset procedure to allow the electronics that control this behavior along with the one touch raise and lower feature to perform a calibration.If your car has this fancy window operation do this reset procedure to see if it helps.

Failing this a solution becomes more work. It could be possible the side window needs some adjusting to cause the window as it goes up to exert a bit more pressure against the rubber seal and stop the leak. The window raise/lower hardware can develop some wear/play over time and the window may not seal/press as hard against the rubber as it did when everything was newer.

To adjust the glass requires a tech who knows the procedure. The door panel has to be removed and any air bag in the door has to be dealt with

There may be another thing you can do/try: In one case with a car that had a very small water leak at the top edge of the driver side window -- a small leak that only allowed a few drops in when I washed the car no water leaked in when the car was parked or driven in rain -- I looked at the window seal. It was U shaped with the outer leg of the U being what the window pressed against and which helped form a water tight and reasonably air tight seal. What I thought about doing was laying a length of rubber o-ring inside the U to cause the outer leg of the U to press against the glass with a bit more force to end the leak.

But because the leak was so very small and only a problem when I washed the car and which I could with a just a bit of extra care avoid causing any water to leak past the glass I never did this. What I did do was wipe down all the rubber weather stripping against which the windows and doors seal with Gummifledge (years ago BMW sold this at its dealer parts counters). This stuff acts to lubricate the seal surfaces -- yet does not attack the rubber! -- so they slide and move as the door or window is closed and thus the rubber is able to make a better seal.

I do not recall now if the use of this ended the leak. But I felt better. If you can get a hold of some Gummifledge it is worth a try. I bought a tube of this stuff years ago shortly after I bought my 2002 Boxster and I still have it. A little of this stuff goes a long way.

 

Thanks for all the feedback! It appears the windows are operating correctly. Your rear vent point is interesting. I wonder if anyone knows where that is on a F56? I did have that rear hatch seal replaced due to water coming in the hatch. It was a TSB from Mini. I now wonder if fixing the leak messed up the vent.

Thanks again!

 

I have to believe all cars have cabin vents, at least every one I have owned and any one you see missing a rear bumper cover. That has been common place for many moons. The vents look like fish gills that allow airflow in a single direction as RockC noted. While the non-recirc setting will create a little cabin pressure, it shouldn't be enough to cause the window seals to whistle.