Ever since I've bought my XF, there has been an "air" sound coming from the back of the vehicle when the doors lock or unlock. I disregarded it because its an air pump. It will make noise. It has gotten progressively worse, and I have discovered that I have an air leak in the tube that goes into the hatch. Now the hatch doesn't unlock everytime, and the pump runs for about 15 seconds, and you can her the leak from outside the car. So, the car will be going back to the dealer, again, to fix that, the wind noise problem, and my diff (80 mph whining). I'll let you know how it turns out.

 

You're right with the pneumatic leak for the door locks... I would worry about the diff noise ! Are you sure it's not the tires ? Ah well only my 2.5 cents !!!

 

That is the only problem I've had with mine (KOW). The lock wont work if the leak gets too bad. Mine took an hour to fix, no big deal, dealer did it. Mine did the same thing. You could hear the hiss then one day I came out from the grocery store and the hatch wouldn't lock.

Pat

 

I realize this was an old thread but my XF is having the same problem. How much did the dealer charge to fix it? Think I could do it myself?

 

Yes you can fix it, most leaks occur when then the air line that goes through the rubber boot on the passenger side of the hatch breaks due to flexing. There are threads that explain the repair.