Weird Noise From Rear When Closing Door

[mido]

I realized today that everytime i close my door there is a significant "thump" noise coming from the rear of the car. This happens with every door not just one. I tried rocking the car but nothing at all. What i realized is that if i have one door open and try to reproduce that noise with another door it wont happen.

If i hold the door handle open and "open , close , close, open , close" fast enough its almost as if someone is literally taking a hammer and banging on the trunk lid. What the heck could this be ?!

[TheMAN]

could be something loose inside the door

[Pokey]

Hatch or sedan? Could the hatch be open slightly and the change in air pressure makes it go boom?

[mido]

Its a 4 door sedan.... Cant be something loose in the door as it happens on all doors.

It doesnt happen if 1 other door is open or if the trunk is open as well. Very weird...

[vip3r87]

I am not sure,

But I am thinking it might be the rear seat-back. When there is a door or trunk open it doesn't happen because the pressure is the same outside the vehicle/inside the vehicle.

Make sense? Try sitting in the back seat with all doors closed, lean back with some force and then open/close the door...chances are if I am right (which I am probably not :P), there will be no clunk

[Nick]

there are vents hiding behind the rear bumper on either side, maybe they are stuck and cabin pressure is being forcefully released through somewhere else

[qwerty66]

its normal...
try sitting in the driver seat, all doors closed but the drivers
bring the door in so its almost closed,
then open the door fast
you should hear the vents make a thump noise as they close

[mido]

Maybe im hearing the vents.. But this is a rather strong thump not an ordinary thump. Ill check out the vents if they seem fine ill take a video and post it ..