Rattling in rear under hard acceleration
 

I have a 2005 4.4i with about 1500 miles. Coming back from my first weekend roadtrip yesterday, I noticed a rattling sound from the rear during full-throttle acceleration. I thought it was coming from my bags in the back, but this morning it's still there. It sounds like it is coming from the exhaust. Does anyone have this same problem?

I don't know if this is the same thing, but I've noticed that my '05 X5 4.4 has always had an unusual sound from the exhaust under full throttle acceleration (around 1500 miles now). I wouldn't call it a rattling...more like a staccato "fluttering" sound...weird.

I swear, the first time I heard it, it reminded me of the sound you got when you attached playing cards to your bicycle to make them flap on the spokes!!

My guess would be a loose heat shield around the exhaust.

Do you have the load floor or the tow hitch?
License plate or holder.
Heat shields. There are four botls that hold each heat shield and are easy to check.
Loose PDC cable?

There are only a few things under the rear that you will be able to look up and check. The other could be loose nuts on the exhaust pipe and muffler holders. There are 5 nuts on each side, two under the lower body mount and three near the bumper.
:dunno:

Thanks for the input, guys. I'll check on those things. I dont have the load floor or tow hitch, so I'm guessing it's going to be the license plate frame or the heat shields.

Fluttering
 

I just got my 06 x5 back from BMW after 4 times in. They replaced my muffler [right side] and found out later it was a heat shield resting on something.....

Hope this helps.......

You do realize this thread is 2.5 years old, right? ;)

Yes.... wanted to help any others who have this...... what a great forum.

Don't all x5's make a fluttering noise? Not very loud but they do make a fluttering exhaust noise. All 4.4i's and 4.8is' I have heard so far have made a little fluttering noise.

Fluttering
 

Check out this gentlemens:

http://www.youtube.com/watch?v=wdYfio0xVkU

I saw/heard this on this forum. My flutter was almost to this degree. My flutter grew and grew. After much checking they found it to be a heat shield resting on tranny or something. My X sound beautiful now.