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I too experience a metallic rattle in any gear between 2600 and 3000 RPMs in my 06 C2S. It is not a good sound i.e. the quality of the sound makes one assume Porsche did not intend it. It is possible to reproduce the sound with the car being still, but it is much more prominent when the engine is under load. I have the PSE. The sound is noticeable from inside the car with the windows up. Is very difficult to discern from outside the vehicle.
Armed with the knowledge from this forum, my independent technician spent approximately six hours chasing this vibration. He checked all the exhaust components, all hangers, heat shields, wired the valves open to ensure there was no movement, and took the mufflers out to inspect them. He did not take the rear bumper cover off. I should mention that I acquired the car with 5600 miles and noticed the rattle even then. It now has about 11,000 miles. Much to my disappointment, he has been unable to identify the source, and has concluded that this may be a normal characteristic of the PSE.
Given the low miles, his conclusion may be correct i.e. there just hasn't been much opportunity for anything to break on this car. It is the only annoyance on an otherwise spectacular car. Unfortunately, the rattle falls within a commonly used cruising rev range. I wanted to post this in the hopes that somebody may have found an alternative cause other than the typical weld fracture, or in one case, a defective oil pump. Could it really be an acoustic characteristic of this exhaust system?
I may begin to address this issue symptomatically if no root cause can be found. I keep my sport exhaust in the sport mode at all times. I love the volume and the throaty nature of the sound. This metallic sound is annoying. I may begin to explore various acoustic treatments behind the rear seats that perhaps will lessen the bleedthrough of the metallic sound while not tempering the sound of the PSE.
OP here - mine has never been found or traced to a diagnosis. I just live with it. My tech says the car and all components are solid, so I'm with the rest of you - amazed that I have to put up with this in a car of this quality and price. I want to enjoy the car, not have it spend time in the shop.
Frankie P - welcome to my world. I just turn up the music to shield myself from the buzzing, metallic rattle.
If anyone has new ideas, please share. I've tried everything everyone has suggested, to no avail.
Any updates on this? My 08 C2S has the buzz/rattle during immediate deceleration between 3000-2500 rpm. Cant seem to find any cracks in the muffler brackets. Anyone have any other solutions or ideas?
Sometimes it's something loose inside the muffler or cat. The only real way to tell is to remove them and bang on them with a dead blow hammer or rubber mallet. Banging on them while still installed on the car can give a false negative diagnosis. But you might get lucky with a true positive diagnosis.
Another thing to check is the rear bumper cross member. There are two bolts holding it to the frame. One of mine was loose causing the cross member to rattle at certain rpm bands, which sounded exactly like an exhaust rattle. The torque spec is 63 ft-lbs.
Thanks Semicycler for the great troubkeshooting tips. I had the bumper off last week snooping around, but did not check the cross member bolts, or disassemble the exhaust. This will give me a chance for some quality garage time this weekend. I will let you know what I find.
Taking Semicycler's suggestions, and others lessons from posters on this thread I spent a wonderful day removing the bumper cover, bumper cross member, the entire exhaust system (part by part to thoroughly check each part independently), and all heat shields. Unfortunately no bolts were loose, and each individual exhaust component is rock solid. The highlight was letting it run un-capped (just headers and cats) for a few minutes - these things (2008 C2S) sound mean and nasty that way- soooo fun! So after thoroughly cleaning all the parts no one will ever see, and re-assembling the car, my test drives resulted in NO improvement in the buzz/rattle when letting off the throttle at 3000 under moderate load. At least I can rule out those 15 parts in my troubleshooting effort.
In my continued efforts I removed and verified the air box, and verified all reachable bolts, nuts, clips, etc, are tight. While "tapping" around on everything, I noticed that the throttle-body rattles when I thumped it on the Left/drivers side. I removed the TB, and carefully removed the black plastic cover. There are three gears inside, and found that the gear on the electric coil shaft is the one that rattles. Not sure if Incan get just that part, or if I should just buy a new TB ($210 at Pelican Parts). I'll post my finding when I do.
Resurrect and old thread, did you found a cause of your noise? Got here exactly the same....
To rule out the usual suspects we changed exhaust, cats, heat shields, drove without bumpers, without belt, checked all coolant, AC, fuel lines from back to front, engine/ gearbox mounts and still same rattling/ metallic noise in cabin around 2800rpm under a very light load/ feathering throttle in any gear.
OP here. Still have my ‘07 C2S with 35k on it. Still buzzes in the same RPM range on the way up the revs and the way back down. Had it in for all the normal maintenance stuff since it’s now 12 years old and driven only a few months a year, and everything checked out perfectly. Still no clue. Just living with it and thinking of this thread every time I hear it!
Not sure about the older cars but my 2019 S does this. I'm almost 100% sure if the PSE valve. There seems to be some end play in the shaft that goes into the exhaust. This might be what's causing it. My buzzing is not there when PSE is off!
11-14-2013, 08:48 AM
