Ok, I know this has been discussed before but I think I have something different, I hope.
My C4S has developed a strange rattle up front when going over bumps (especially smaller ones), happens on both the up and down (like rattle rattle rarrle rattle). Now for the weird part, it doesn't happen when you first get going, or when your driving, only at low parking lot type speed. Any thoughts?

 

I guess the problem is the strut mount of the front suspension. you may take the cap off to check if there is any movement.

 

+1

It sounds like your strut mounts and strut bearings need to be replaced. I had mine replaced back in January of 2011 for similar symptoms at 96,587 miles. I had the work done at a Porsche dealer. The total with parts and labor was: $1,424.36.

 

I'll check it out, I looked at it yesterday and there was no sign of wear anywhere, even the bearing looked nice and intact. I'll pull the cap off later to see if the top nut may be loose.
But you know, the noise sounds lower and closer to the front of the car.

 

I had a very similar problem, but it was so outlandish that I don't think it is the same issue for you. Both my front a-arm bolts had rattled and fallen off. The a-arm is still held on by the rear bolts, but this caused significant rattling while going over bumps as well as steering wheel shake while slowing/braking.

 

I went home at lunch and looked at the struts from the underneath, and everything looks good, in fact almost new! In fact the strut stop, stop plate, and bellows all looked new as well. I mean no dirt and still had writhing on them.
I'll have to look at the sway bars etc..

 

This probably isn't it, but you haven't recently put anything in the trunk up there that might be moving around when you hit bumps have you? Hope you get it sorted out soon!

Swaff

 

No, but this did cross my mind as well, I'll take the little tool bag out and see. Hey, you never know!

 

Ok, well I looked at the struts up and down and everything seems normal, no cracked bearing all tight, in fact as I mentioned before, they almost look ner, no rust to signs of warn rubber....So, it must be something else, like sway bar, drop link, I'll keep looking.

 

On my ex C2, it was the drop links. They looked fine, but after changing them, the noise went away.

 

Gotcha, I'll have a look...thanks

 

x2

Also if the droplinks aren't fully broken, it's sort of hard to check with them bolted up. You would need to unbolt one end at least to move them and check for any looseness or rattle.

 

Ok, thanks. I think I'm off to the shop and let them have a look see. The strange thing is you don't hear it until the car's been driven a while, like going out of the neighborhood no noise, returning you hear it, and never while driving around at normal speeds..?????

 

Did you get a prognosis from the shop yet?

Swaff

 

No, I've been lazy over the last couple of days I'll do it in short time though. I'll let you know what I find out.