Yesterday, I was running a quick errand and noticed a whinning sound, similar to a vacum leak but its loud. I think it maybe the drive belt or pulley but it just annoying. There is no loss of power or check engine lights coming on. I'm lost and Jaguar told me they cant get me in until the following Wednesday!! Any help would be nice or any advice would be greatly appreciated. 2007 Jaguar xk 4.2 I attached a video link. ....Please help

 

Drew, you need to pull some of the plastic out of the way. Once the covers are off, the problem may become obvious. With all the covers in place best guess is as you said, a belt or pulley. I can't remember ever hearing a vacuum leak sound like that.

 

I don't believe it is a vacuum leak. It sounds more like a bearing or belt. It varies with engine speed so I would consider , power steering pump , alternator or compressor. I would also not drive it until you find the source .

 

The very last frame of your video shows the air intake tube (which is tuned for specific sound in the XK, some of which is filtered back into the cabin). *you are missing the rubber support grommet for the piece that runs back towards the windscreen* Compare this area on your engine with that shown in the photo below from my 2007 XK. Note the sturdy grommet that supports this part of the air intake tube - could the noise be a vibration or otherwise related? In any case this grommet should be replaced on your car - Jaguar rarely fits unnecessary parts!

 

Guys it was the alternator. Took it to Henessy in Atlanta they said it was all the belts and pulleys lol wanted me to pay 2500 to fix it all. Drove a block down the road and the no battery charging light comes on. Lost all power and had to get towed. Trying to see if anyone knows how to take the alternator off this model. 2007 xk.