Last night driving home I heard something I thought clunk under the car (2008 CayenneGTS) so I pulled over to look around. I didn't see anything obvious, so I drove with the windows down in the parking lot to see if I heard anything unusual, which I really didn't. By the time I got home it sounded like someone took a metal spoon and was stirring it in a dry metal pot. What was weird is that the noise at full steering lock in reverse isn't there but he's a whole lot worse when driving forward. It can not be heard windows up and 45mph plus or I would have had it towed home. This morning I looked all around and couldn't find anything, but still the same problem. I did notice the brake rotor backing plate bent but it didn't appear to be touching and I coluld not assess if there is something really wedged in there. It's easy to say "there is a rock or debris back there" but how can you tell without disassembling the brakes?

Really afraid to drive it at this point. My neighbors were giving me the look as I was outside pulling it forward and the screeching could be heard echoing.

I think I will have it towed to Porsche tomorrow morning if they are open, but I would be happy to hear any advice or experience with something similar. I have been searching the forum all morning but only read similar symptoms not a cure.

 

Does the sound change with revs/vehicle speed?

If not it could be the water pump.. hard to tell just from your written description but my car made a metal spoon stirring in a dry metal pot sound constantly. My dealership immediately diagnosed it as a failed water pump.