I've had a rattle in the back of my CS for the last 2 months.
It was like a plastic bolt rattling but was worse going over very small bumps: thick paint lines in the road etc

I searched on here for advice and went through all of the possibles:
trunk/clunk- no
seat belt bolt- no
rear side window- no

I had sort of narrowed it down to the rear 3/4 area behind the passenger (driver side in the USA).

I bought some trim removal tools and started packing various parts of the trim with rubber foam where there was plastic on plastic

rear light assembly- nope
strut cover- nope
rear hatch lifting strut- nope
storage cubbt- nope

Then FINALLY as I was poking around in the rear hatch area I tapped the carpet on top of the engine cover... there it was!!!

Tappy, clicky, tappy sound.

Out with the trim removal tools and I packed some foam between the carpet and the metal cover on the edge facing you as you open the rear trunk.

Rattle....GONE!!!!

I've driven it for 6 days now and NO RATTLE!!! (in the past I thought I had solved it only for it to return the next day)

I figure the sound came and went depending how hot the engine was: hot- cover and carpet expand = no rattle.

Also the acoustics of the rear of the car made it seem like it was coming from the corner when it wasn't.

Just thought I'd share the tip and maybe save someone the madness I've endured for so long.

thanks blueyes,

i think i had this prob but it went away on it's own (!?) ... anyway, if it ever comes back, useful info ....

__________________

To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts.

______________________
2007 Cayman S Tip ; Softronic Flash ; H&R Sport Springs

So glad someone else has this prob... was driving home last night and it started.. same thing.. sounds like almost plastic buzzing rubbing hitting glass ??? Almost a vibration.. and sounds like it could be the brake light.. I am going to try your quick fix.. thanks for posting... Aloha Hudson

hey hudson...where have you been? although i listen to you (and scotty) every morning, you've been mia from the forum. good to know that you're still visiting.

I have had various rattling sounds since I took delivery the car in July 2006. The dealer never hears anything, and with this being my first Porsche, I'm a bit deflated with the noises. I thought it was the rear hatch, or the pillar, but I didn't think of the engine cover. Thanks.

When I fist picked up my 06 CS I heard a couple of rattles. They drove me nuts and had to have the window down to drown out the sound. I took it in twice and of course they couldn't hear the rattles. The second time as I drove out of the lot I heard both noises. I turned around and took the service manager out. By some miracle he suddenly heard them. One was the from the passenger side door pillar between the door and side window. The other was from the driver side air vent. He then made an unbelievable statement. They won't fix any rattles that occur over 65 mph. I told him that was not in any warranty and that he was going to fix the rattles. I also said I had no problem dropping him off right there on the freeway and driving to another dealership for all of my vehicle needs. The repairs were done that day.
Mike

I had the same problem with rattles coming from the back, sort of a vibrating buzzing sound that would become louder over bumps and road irregularities.

When removing the engine cover I found the torx screws loose, not even hand tight.
After cleaning the engine (getting ready for Tess Tickle's clear engine cover) when replacing the cover I tightened the screws and ...... NO MORE RATTLES. Hope this helps someone.