Exhaust Rattle C63S coupe.
Just to make sure, what @untamed did is something like this?
Just to make sure, what @untamed did is something like this?
ps nothing wrong with trying to make it look as stock as possible but the dealer will look at the weld and say its not stock so thats something to keep in mind as well.
For most of you that know me, I went through this ordeal as well. And found that it was a faulty H Valve.
For anyone interested, I have an AWE H PIPE with a (non-working) valve, that I would let go cheap. (The actual H-Pipe and craftsmanship are amazing)
This would be a perfect solution for someone looking to have a permanently open/closed H-Pipe.
PM for info if interested
Last edited by FLC63s; Oct 26, 2019 at 10:36 AM.
The Best of Mercedes & AMG
My dealer was very good to me and they are going to replace exhaust flaps even though I have a modified H pipe etc.
This dealership has always treated me well so that is a bonus. Helps that I have bought 4 new AMGs in the last 5 years from them.
Interesting that this issue still is present in brand new cars, seems to be an area that they need to sort out from factory ASAP.
The problem is weak tension in the on the three exhaust flaps L, R & Center. Request that your dealership open a PTSS Case with MBUSA Engineering and they'll get to the solution much faster - the tension needs to be increased on all three flaps. My car had 3 exhaust systems replacements and the rattling always came back - it took my dealer 8 weeks to identify the issues and 2 days to fix it once opening the PTSS case with Engineering.
Good luck!!
RM
(actually the valve actuator with a new special grease).




(actually the valve actuator with a new special grease).Are you in Sydney? Could you tell me which good dealer you went to?
Last edited by Jimmy_c63s; Dec 26, 2019 at 09:32 AM.
Are you in Sydney? Could you tell me which good dealer you went to?
I'm pretty good at reproducing the sound now and this is how I did it:
1. Exhaust valve open. Window down.
2. Select gear where you can do a pull from 2000-3500 rpm safely and within speed limits.
3. Use about 30% throttle.
You can make the noise even more noticeable if you are driving next to a wall or brick fence (because it reflects the sound back). I requested a tech to ride along with me, made the sound happen and they agreed it was not something that should happen.
I'm asking my service guy now for the XENTRY Tips reference for the issue and will post it here once I get it.




I'm pretty good at reproducing the sound now and this is how I did it:
1. Exhaust valve open. Window down.
2. Select gear where you can do a pull from 2000-3500 rpm safely and within speed limits.
3. Use about 30% throttle.
You can make the noise even more noticeable if you are driving next to a wall or brick fence (because it reflects the sound back). I requested a tech to ride along with me, made the sound happen and they agreed it was not something that should happen.
I'm asking my service guy now for the XENTRY Tips reference for the issue and will post it here once I get it.
If anyone else has any tips, experiences or ideas please update this thread. This is something that needs to be addressed and seeing as many of the 2016 cars are out of warranty now, I'm sure others would benefit

Last edited by Jimmy_c63s; Jun 12, 2021 at 03:32 PM.
Okay so here's an update, I've managed to make the rattle almost barely noticeable now.
Basically, went under the car and removed the exhaust flap actuator (motor) from the H-pipe and used White Lithium Grease spray and re-seated the spring. Worth a try before shelling out on a new exhaust.
It's pretty easy to access the H-pipe, I only jacked up one side of the car and used a a size 8mm socket (and spanner for the bolt at the top, closest to the heat shield).
The three bolts are a bit of a pain especially the bolt at the top. A spanner is best for the bolt at the top. Once that's taken off, you can remove the entire valve motor.
Side view of the "spring". Once you remove this motor, the H-pipe exhaust valve can be freely opened and closed with your finger. It's actually not very tight and moves very freely. By moving it with your finger, you can pretty much hear that rattle sound by moving the flapper on the H-pipe.
If you are looking for part numbers, the Exhaust Valve Motor for the C63S with AMG Performance Exhaust is A1909064500 and the plug is A0225452426.
Apply a very small amount of White Lithium Grease (about the size of a penny) where the spring is seated.
Also apply some around the actual exhaust flapper on the H-pipe where the spring of the motor sits. Make sure the spring is sitting nice and tight too.
Here is a view of the back of the exhaust flap motor
Refit the H-pipe valve
Doing this and making sure the 3 bolts that hold the actual exhaust flap motor to the H-pipe are nice and tight has made a massive difference. The rattle is no longer a "kriikriikrii" noise and more of a very low volume "crukcrukcruk" but barely there.
I would still prefer it to be completely gone so I will be waiting to hear if the dealer will honour the repair.
If anyone else has any tips, experiences or ideas please update this thread. This is something that needs to be addressed and seeing as many of the 2016 cars are out of warranty now, I'm sure others would benefit





I'm wondering if permanently closing the valve will cause any effects like loss of power? Would the car still be quiet in "quiet/comfort" mode?








Okay so here's an update, I've managed to make the rattle almost barely noticeable now.
Basically, went under the car and removed the exhaust flap actuator (motor) from the H-pipe and used White Lithium Grease spray and re-seated the spring. Worth a try before shelling out on a new exhaust.
It's pretty easy to access the H-pipe, I only jacked up one side of the car and used a a size 8mm socket (and spanner for the bolt at the top, closest to the heat shield).
The three bolts are a bit of a pain especially the bolt at the top. A spanner is best for the bolt at the top. Once that's taken off, you can remove the entire valve motor.
Side view of the "spring". Once you remove this motor, the H-pipe exhaust valve can be freely opened and closed with your finger. It's actually not very tight and moves very freely. By moving it with your finger, you can pretty much hear that rattle sound by moving the flapper on the H-pipe.
If you are looking for part numbers, the Exhaust Valve Motor for the C63S with AMG Performance Exhaust is A1909064500 and the plug is A0225452426.
Apply a very small amount of White Lithium Grease (about the size of a penny) where the spring is seated.
Also apply some around the actual exhaust flapper on the H-pipe where the spring of the motor sits. Make sure the spring is sitting nice and tight too.
Here is a view of the back of the exhaust flap motor
Refit the H-pipe valve
Doing this and making sure the 3 bolts that hold the actual exhaust flap motor to the H-pipe are nice and tight has made a massive difference. The rattle is no longer a "kriikriikrii" noise and more of a very low volume "crukcrukcruk" but barely there.
I would still prefer it to be completely gone so I will be waiting to hear if the dealer will honour the repair.
If anyone else has any tips, experiences or ideas please update this thread. This is something that needs to be addressed and seeing as many of the 2016 cars are out of warranty now, I'm sure others would benefit

Thanks men.
I'm going to test this weekend.
Is valid for rear valves?
My rear valves sound like a old door open/close when I open/close the car or use the valve button.
Thanks.








Take off the valve motor and inside the metal "funnel" section also apply some White Lithium Grease on the top of the actual exhaust flap spindle. You'll see this round spindle once you remove the black plastic exhaust flap motor assembly. That's what's causing the squeak in your back boxes (thanks to Alex for the pic).


