I had a problem with wind noise from the front doors on my E92. The resolution was to adjust the window preload; this is effectively the angle of the door glass relative to the body, moving the top of the window closer to the car or farther away. With any job like this, patience is the key - you need to make small adjustments then check what difference you've made, repeating as required.

Tools required
Masking tape (for marking)
Ratchet (I used a 3/8", but a 1/4" should work too)
12"+ extension bar for your ratchet
Hex bit holder for your ratchet
10mm socket
Torx T40 bit (for door striker to body bolts, if needed)
Torx T15 bit
Flashlight
Trim removal tool (or taped-up flat screwdriver)

Prerequisite
Before you adjust the window, you need to check that the door striker is correctly positioned. With the door closed, look down from above at the gap where the door meets the rear side panel. The edge of the door should line up exactly with the bodywork behind it. Check by placing a non-scratch straight edge across the gap in a few places.
If it's consistently out (i.e. the rear edge of the door is recessed or, more likely, proud), you should adjust the striker (outwards or inwards respectively). This is the silver metal hoop attached to the B-pillar that the door lock mechanism engages on.

1. Mark the striker position with tape.
2. Loosen the two Torx T40 bolts just enough to move the striker (less than 1/2 turn).
3. Ease the striker in the appropriate direction, using your tape markings to make sure you move it by the same mount at the top and the bottom. Move it towards the centre of the car to pull the door in or towards you to move the door outwards.
4. Move by about 1mm, then tighten the bolts and re-check the alignment - repeat 2-4 as required.

You can see here how I marked the position with tape.


Method
Once you've confirmed the door is correctly positioned, you can move on to adjusting the window preload. The ideal position for the window is such that, if you close the door onto the first catch (i.e. not closed all the way, but you can't open it without using the handle), the window is just touching the seal at the top. If there's a gap, you should adjust the preload.

1. Open the door and locate the two rubber bungs at the rear corner. The larger is on the rear edge of the door facing you, and the smaller is just underneath the door. Larger is circled red here.
   
2. Use your trim tool or taped screwdriver to pop the bungs out of the door.
3. If you shine your flashlight through the larger hole, you should see the adjuster mechanism in front of you (circled red):
   
   That adjuster is made up of a shaft with a Torx T15 hole in the end (red) with a 10mm locknut around it (blue):
   
   The shaft has a toothed cog on the end that moves along a track to push the bottom edge of the window regulator inwards or outwards, which moves the top edge of the window outwards or inwards respectively.
4. If you shine your flashlight through the smaller hole under the door, you should be able to angle it so you can see the adjuster whilst you're using the ratchet through the larger hole.
5. Use your ratchet, extension and 10mm socket to loosen the nut on the adjuster by about half a turn, just to free the mechanism.
6. Use your ratchet, extension, bit holder and T15 bit to turn the Torx fitting on the adjuster - one way moves the bottom of the window in and the other way moves it out, depending which door you're working on.
7. At this point, it's just trial and error. Make an adjustment, tighten the nut to secure it then close the door to the first catch. If the window touches the seal, it's OK; if not, adjust it some more!
8. Once the window touches the seal, tighten the nut with the 10mm socket then get in the car, close the door and check the operation of the window. If it still runs up and down smoothly, you're done. If not, you might need to back off the preload slightly.
9. Assuming you're happy, put the rubber bungs back in the door then do a road test to confirm the wind noise is gone.

Let me know if you've got any questions...

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2007 E92 335i SE auto | Monaco Blue | Cream Beige | Quaife LSD | Birds B3 ARBs | Evolve Stage 1 | CIC retrofit