Exhaust rattle 2005 911 S with Sport Chrono

[pjw72]

I purchased a CPO 2005 911 S cab with low mileage and an exhaust rattle that seems to occur around 2500 rpm and half throttle. Doesn't seem to happen if I drive it in sport mode. Dealer sprayed some lube on the exhaust butterfly valve - made it a little less common, but still there. I do not have PSE, just sport chrono.

I read about a recall on the early 2005 exhausts, but cannot find the recall section on this site (if there is one - only found the TSB section but no recall info). Also, searched the forums but can not find any info, so I am sorry if this is a repeat question.

Can anyone help?

thanks

Josh

[AP 997S]

What is an 'exhaust butterfly valve'? If your car doesn't have a PSE then the exhaust system is 100% passive (ie no valves). I think there is a valve of sorts in the intake system that makes the motor 'rattle' a bit when it's fired up. It closes when the fuel or air is purged.

The recall you might be referring to could be the 'exhaust tips' one. Porsche recalled early VIN's due to a poor weld on the exhaust tip assembly. They were afraid it might cause the tip or tips to fall off and cause a problem to trailing cars. Have your dealer do a search in their computer system by your VIN to see what recalls have been done or should be done.

Congratulations on your purchase. I own a 2005 997S as well and love it.

Edited March 11, 2009 by AP 997S

[pjw72]

Not sure exactly what butterfly valve they were referring too. When I hit my sport button it gets much louder, something is def changing in the exhaust. I was told by the dealer it only has sport chrono and not the PSE, but they may have been wrong.

This is my first Porsche and I am disappointed I waited this long :-)

What is an 'exhaust butterfly valve'? If your car doesn't have a PSE then the exhaust system is 100% passive (ie no valves). I think there is a valve of sorts in the intake system that makes the motor 'rattle' a bit when it's fired up. It closes when the fuel or air is purged.

The recall you might be referring to could be the 'exhaust tips' one. Porsche recalled early VIN's due to a poor weld on the exhaust tip assembly. They were afraid it might cause the tip or tips to fall off and cause a problem to trailing cars. Have your dealer do a search in their computer system by your VIN to see what recalls have been done or should be done.

Congratulations on your purchase. I own a 2005 997S as well and love it.

[Loren]

Most exhaust rattles are either heat shields, loose connections or a broken weld in one of the mufflers.

[AP 997S]

Not sure exactly what butterfly valve they were referring too. When I hit my sport button it gets much louder, something is def changing in the exhaust. I was told by the dealer it only has sport chrono and not the PSE, but they may have been wrong.

This is my first Porsche and I am disappointed I waited this long :-)

What is an 'exhaust butterfly valve'? If your car doesn't have a PSE then the exhaust system is 100% passive (ie no valves). I think there is a valve of sorts in the intake system that makes the motor 'rattle' a bit when it's fired up. It closes when the fuel or air is purged.

The recall you might be referring to could be the 'exhaust tips' one. Porsche recalled early VIN's due to a poor weld on the exhaust tip assembly. They were afraid it might cause the tip or tips to fall off and cause a problem to trailing cars. Have your dealer do a search in their computer system by your VIN to see what recalls have been done or should be done.

Congratulations on your purchase. I own a 2005 997S as well and love it.

If the exhaust sound increases when you're in 'sport mode' than I have to assume you have a PSE.

There are many ways to tell if you have a PSE. The most visible is if the exhaust tips (chrome plated) are different sizes (diameter) and offset. The standard (non PSE 997S) stainless tips that are equal in size. It's easy to spot the solenoid that activates the PSE 'valves' and if look underneath you'll be able to see the actual vacuum operated valves that attach to each muffler. Do a search on this forum or others. There are plenty of pictures that will help you. This forum has the install procedures in their technical archives that will certainly help spot things. I am surprised that you got little help for your Porsche dealership.

Loren's suggestion of loose or broken parts may also be a factor but I think when you said the exhaust level increases when you push the 'Sport Mode' button it sort of points to PSE. If you do have a factory installed PSE then it will cut out if you fall beneath a certain speed. Germany has some noise regulations that Porsche had to abide with and so they simply made the PSE DME (main computer) controllable.

It now makes some sense that the service action was to lubricate the 'butterfly valve'. Maybe it was sticky or not working correctly. Of course if that didn't fix the problem you might have a faulty muffler/valve. In any event it should be covered under your warranty (assuming it's still active). If you have no warranty left possible the exhaust system is covered under the emissions warranty which I believe is longer than the 4 yr period. I could be wrong.

Good luck and keep us posted.

[csman]

Not sure exactly what butterfly valve they were referring too. When I hit my sport button it gets much louder, something is def changing in the exhaust. I was told by the dealer it only has sport chrono and not the PSE, but they may have been wrong.

This is my first Porsche and I am disappointed I waited this long :-)

What is an 'exhaust butterfly valve'? If your car doesn't have a PSE then the exhaust system is 100% passive (ie no valves). I think there is a valve of sorts in the intake system that makes the motor 'rattle' a bit when it's fired up. It closes when the fuel or air is purged.

The recall you might be referring to could be the 'exhaust tips' one. Porsche recalled early VIN's due to a poor weld on the exhaust tip assembly. They were afraid it might cause the tip or tips to fall off and cause a problem to trailing cars. Have your dealer do a search in their computer system by your VIN to see what recalls have been done or should be done.

Congratulations on your purchase. I own a 2005 997S as well and love it.

If the exhaust sound increases when you're in 'sport mode' than I have to assume you have a PSE.

There are many ways to tell if you have a PSE. The most visible is if the exhaust tips (chrome plated) are different sizes (diameter) and offset. The standard (non PSE 997S) stainless tips that are equal in size. It's easy to spot the solenoid that activates the PSE 'valves' and if look underneath you'll be able to see the actual vacuum operated valves that attach to each muffler. Do a search on this forum or others. There are plenty of pictures that will help you. This forum has the install procedures in their technical archives that will certainly help spot things. I am surprised that you got little help for your Porsche dealership.

Loren's suggestion of loose or broken parts may also be a factor but I think when you said the exhaust level increases when you push the 'Sport Mode' button it sort of points to PSE. If you do have a factory installed PSE then it will cut out if you fall beneath a certain speed. Germany has some noise regulations that Porsche had to abide with and so they simply made the PSE DME (main computer) controllable.

It now makes some sense that the service action was to lubricate the 'butterfly valve'. Maybe it was sticky or not working correctly. Of course if that didn't fix the problem you might have a faulty muffler/valve. In any event it should be covered under your warranty (assuming it's still active). If you have no warranty left possible the exhaust system is covered under the emissions warranty which I believe is longer than the 4 yr period. I could be wrong.

Good luck and keep us posted.

I have the same problem on my 05 C2S coupe with sports Chrono and PSE (which it seems you must have). Visited a reputable independent specialist yesterday who checked the exhaust but said before and afterwards that it was the valve actuator/butterfly that seems to cause this on some cars. After checking he thought that his initial diagnosis was still correct. There is no easy fix but equally it causes no damage so unless it is under warranty or really annoying you it's best to live with it (as I have decided to do). Call it character!

Cheers

csm