thanks for the details. Will it be necessary to remove the mufflers to work on this or I imagine a car lift will make things easier?
also when you say pull out the old spring, is that just a simple pull and insert new one or any tools required for it?
this can all be done with the muffler on, no need to remove…you just have to get under the vehicle. I used race ramps to get under my SUV. On the spring, no tools needed, just pull it out and it comes off easily.
You'll need new exhaust actuators. I'd bet the spring has snapped on one which would have been the bang you heard.
Either way you'll need actuator motors and Mercedes aren't cheap (huge rip off).
If you're out of warranty get 2 x Audi ones they're a lot cheaper. I've got two Audi ones in my rears on my performance exhaust. The part no. 4H0133246J for the Audi actuator they are all the same oem Kuster brand actuator for a wide range of cars from Volvo, Ford, Audi VW, Mopar, AMG and all work (tested a few of them).
The Ford actuator is the cheapest of the lot. Part no for that one is FR3Z-5K245-A.
Just to update on this piece of advice
My actuators on my 2019 FL C63S failed, spring broke and the actuators were quite weak. I ordered the Audi part as stated above, but when we went to install it, it wouldn't work. So we will have to go with the original mercedes parts in the end.
I don't blame anyone for this, as it was a shot in the dark - but maybe it doesn't work on the facelift cars?
Just posting here in case anyone else is in the same position as me, and tries to use a different branded part as a replacement.
this can all be done with the muffler on, no need to remove…you just have to get under the vehicle. I used race ramps to get under my SUV. On the spring, no tools needed, just pull it out and it comes off easily.
did this today and it sounds better but unfortunately still some of that rattle that i noticed with window down and when passing another car
Did you replace springs in all 3 valves? Mine had one in the h pipe in the center towards middle of car, and then one on each side of the muffler
h-pipe i got rid of the valve long time back so i only did the two mufflers.
Will check again on next drive but might just have to buy a couple more valve simulators to get rid of this rattle permanently coz realistically there is no point where i have the valves closed anyway.
I recently purchase a Zak Motorsport exhaust for my 18' C63S and had to extend the rear wires because the valves are more forward than the factory position... So when I was checking out the rear valves to make sure they were working I also noticed that sometimes they are only partially open... If I push the button a couple of times they will open fully. They are brand new valves in the exhaust and move easily by hand so nothing is stuck. I contacted Zak Motorsport and they stated that there has to be some coding done to the ECU to command them open 100% when the button on the center console is pushed.
Also for consideration, is that the 3rd H-pipe valve is not attached to the new exhaust, rather they instruct you to zip tie it to the cross brace right above it and leave it plugged in, presumably to keep the computer happy. I used Xentry to check for codes and I do have a code for the 3rd Exhaust Flap (the code just says "runtime error" )... I contacted Zak Motorsport again, and they think that is because the servo doesn't encounter any resistance or hard stop of the valve and is setting the code (no CEL on the dash though). Again... Zak Motorsport says its something that can be coded out with an ECU tune (presumably the third valve actuation). So I'm wondering if the car is only opening the rear valves partially due to the H-pipe valve issue? Perhaps something with backpressure and the turbos??
I'm thinking of trying a AWE Tuning valve simulator in the third exhaust valve connector. Has anyone tried this? And does anyone have a valve simulator they would be willing to sell (AWE only sells pairs).
I found replacing the spring to be best fix. Copper Grease did not work for me. You can buy the spring from Dodge for less than $40. Part number 68319331AA
Thank you so much for this, had the shop replace the spring while the car was in the air for an oil change today. So happy to be rid of that rattle!
Hi ! I bought a s205 from 2016 and I have at least the 2 rear acuators dead. Valves stay closed. I remove one and I plan to remove the second, do I expect to have a limp mode ?
anything to do to fix the actuators ? They don’t turn at all. Any fuse to check before ?
thanks guys, it’s a pity to drive with the valves closed
I have installed the AWE simulator where the third valve was located and there is no more soft code. I think the rear valves are also opening fully and more definitively when I push the button on the center console. I have one AWE simulator available if anyone needs one for this purpose.
Hi ! I bought a s205 from 2016 and I have at least the 2 rear acuators dead. Valves stay closed. I remove one and I plan to remove the second, do I expect to have a limp mode ?
anything to do to fix the actuators ? They don’t turn at all. Any fuse to check before ?
thanks guys, it’s a pity to drive with the valves closed
I have installed the AWE simulator where the third valve was located and there is no more soft code. I think the rear valves are also opening fully and more definitively when I push the button on the center console. I have one AWE simulator available if anyone needs one for this purpose.
where are you based i had the awe simulator in their changed the rear two actuators still supposedly got this fault so im assuming that my middle sensors gone knackered
ahhh haha I’m in the uk still no luck with this issue though I’ve tried plugging delete valves on the rear two exhaust valves and nothing seems to get rid of the exhaust issue I’ve read on other forums that the a45’s are suffering with the same issue but supposedly the thermostat has solved it for them no clue as to what it is for the c63s
I unplugged 2 rear motors and no limp home mode even if the engine screen display only 350kw instead of 370kw 😅
I found 3 motors (new) on ebay for audi (same ref). I hope it will works.
Anyway I found the exhaust way to quiet compare to my previous panamera 4.8 naturally aspirated (pse and resonator deleted).
What I can do? Remove secondary cata? I was expected a lot more from AMG😭
I personally had an exhaust installed on my car that uses pneumatically controlled valves fed from the vacuum line, however, my car must've triggered limp mode during its installation months ago for whatever reason. I have installed the AWE exhaust modules to trick the existing sensors for the nonexistent valves, but my car will not seem to get out of limp mode. I have taken it to more than one shop who have tried different things such as clearing the system from the soft limp code, but nothing has worked. The second the car hits 4k rpm it dumps all boost and my power never peaks past 330hp off of the gauges. I have no clue how to fix this limp mode and I have searched all over this forum. Please let me know if anyone has information on how to fix it as I feel hopeless at this point
I unplugged 2 rear motors and no limp home mode even if the engine screen display only 350kw instead of 370kw 😅
I found 3 motors (new) on ebay for audi (same ref). I hope it will works.
Anyway I found the exhaust way to quiet compare to my previous panamera 4.8 naturally aspirated (pse and resonator deleted).
What I can do? Remove secondary cata? I was expected a lot more from AMG😭
The Audi ones will work for sure I've tested them all 👍
Fix the valves and grease the flaps first as this will enable them to work properly in sync with the middle (H-pipe-) flap which opens and closes depending on the RPM. Once it's all sorted you'll be surprised at how loud it is when all flaps are functioning especially if you have the coupe/cab.
I unplugged 2 rear motors and no limp home mode even if the engine screen display only 350kw instead of 370kw 😅
I found 3 motors (new) on ebay for audi (same ref). I hope it will works.
Anyway I found the exhaust way to quiet compare to my previous panamera 4.8 naturally aspirated (pse and resonator deleted).
What I can do? Remove secondary cata? I was expected a lot more from AMG😭
limp mode is only past 5k revs i5: a soft limp
Secondary cat and h pipe would make a big difference
Ok guys, so I think the solution by tensioning the spring works really well. Atleast it has been working great for me so far. So no rattles at the moment. If it acts up again, I will go to the welding route.
Now for clear instructions this time:
1) Open the 3 bolts of the valve controller and motor and take it off.
2) You can fix these two ways. One is tensioning the spring and the other way is to weld the valve shut permanently.
Tensioning Spring Method:
Method 1: Tensioning Spring
You will see this rotary dial (picture below) which turns the main butterfly valve. Turn the valve all the way clockwise until you hit the hardstop (valve open position). This position is default anyway when you take the valve controller off.
You will now take the spring off the controller and try to turn the top portion of the spindle anticlockwise. This will put more clockwise force on the rotary dial on the butterfly valve eliminating the rattle. The valve controller will be difficult to install once you do this, which is kind of the point. This fix keeps everything stock and gets rid of the rattle. Spray some high temp grease on the motor spindle (where it holds the spring for good measure).
Method 2: Weld Valve Shut
I will pursue this route if the rattle comes back. Take the spring out of the valve controller, so the motor can rotate freely. This way you will get no codes and no need to disconnect the valve controller. If you take the spring out, the motor spinning force will never reach the butterfly valve.
Then turn the butterfly valve rotary dial anticlockwise until you hit a hardstop. This will close the butterfly shut, basically shutting the H pipe off (imagine having no H hipe at all). Then spot weld the rotary dial at the blue mark I painted. You can choose any other location as well but I think the blue spot is the most ideal place. This from my knowledge of welding should be reversible if you ever want to go back to the original setup.
This worked wonders for me...followed the 1st option step by step. No more rattling.
I first went overboard twisting the spring anticlock. Please note a few mm will do. It was hard to align afterwards but got it right at the end.
This worked wonders for me...followed the 1st option step by step. No more rattling.
I first went overboard twisting the spring anticlock. Please note a few mm will do. It was hard to align afterwards but got it right at the end.
Thank you so much mate.
Hi All,
I'm happy to share that the rattle is gone now. I initially tried the 2nd method but ended up using the 1st method, which worked like a charm(stretch spring & apply Permatex). I'm not a big fan of the rough idle and drone at certain RPMs that came with the second option. But anyway, glad it solved the issue. Thank you all for sharing!
C63s coupe 2024 owner here, I have read every post in this thread looking for a solution.
Been getting that's annoying rattle around 3k RPM since day one and it's the worst thing on this car (that and the brakes squeaking...)
My H Pipe has been replaced 3 times now under warranty and every time they say the rattle is gone but it keeps coming back so I tried copper grease and that didn't work
I decided to take it to a local exhaust shop, remove the actuator and the spring and weld the H Pipe valve shut thinking this would eliminate the rattle. Got in all excited and unfortunately it hasn't fixed the problem.
I don't know what else to do as I figured welding it shut would be the ultimate solution to fixing this since the valve can't move at all. I'm really frustrated and looking for some advice.
Do I need to do this to all 3 exhaust valves or only the H Pipe one?
My next step would be cutting out the H Pipe, welding in a new section with a solid piece closing it off and plugging the actuator in and cable tying it somewhere out of the way to avoid CEL and limp mode. But I can't see how that would work any better than what I've done.
I just would love to enjoy the car and exhaust note without that scrappy rattle, maracas noise all the time.
Please help if you can by sharing your experiences, I've found this thread a great read and would appreciate some more assistance thanks.
C63s coupe 2024 owner here, I have read every post in this thread looking for a solution.
Been getting that's annoying rattle around 3k RPM since day one and it's the worst thing on this car (that and the brakes squeaking...)
My H Pipe has been replaced 3 times now under warranty and every time they say the rattle is gone but it keeps coming back so I tried copper grease and that didn't work
I decided to take it to a local exhaust shop, remove the actuator and the spring and weld the H Pipe valve shut thinking this would eliminate the rattle. Got in all excited and unfortunately it hasn't fixed the problem.
I don't know what else to do as I figured welding it shut would be the ultimate solution to fixing this since the valve can't move at all. I'm really frustrated and looking for some advice.
Do I need to do this to all 3 exhaust valves or only the H Pipe one?
My next step would be cutting out the H Pipe, welding in a new section with a solid piece closing it off and plugging the actuator in and cable tying it somewhere out of the way to avoid CEL and limp mode. But I can't see how that would work any better than what I've done.
I just would love to enjoy the car and exhaust note without that scrappy rattle, maracas noise all the time.
Please help if you can by sharing your experiences, I've found this thread a great read and would appreciate some more assistance thanks.
Oh man. If you've read the thread prior you'll see that welding it closed shut will screw the noise up and causes it to drone. It also will cause the car to have soft limp mode without an exhaust simulator. But simulators don't work on facelift cars.
All you need is one big clump of copper grease as it acts as a cushion to stop the spindle from rattling. The copper grease also doesn't "harden" unlike Mercedes's silver paste they use.
If you want to, increase tension and order a bigger springs from Mopar but from my tests a good amount of copper grease works on it's own you'll just need to apply it once per year.
If you're certain the grease alone doesn't work, get the Mopar springs, add some copper grease and you're 100% set.
Mopar part no. is 68319331AA
Now, unless the welds can be removed you'll need a new h pipe to restore that signature sound and remove the limp mode. Please don't weld or cut off anything else.
Guys please don't weld anything or close the h-pipe permanently. This is not the solution. I've done it all and it's not the way to go.
I've posted and tested fixes for this over the past 5 years and documented my results so many times on this and even on social media here:
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
