Exhaust squeak after rev with C63

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wilko91

New Member
Joined
Jan 6, 2022
Messages
11
Location
Cheltenham
Car
2017 Black C63 Convertible
Hi all,

Wondering if anyone has had any sqeaking from their exhaust flap(?) after revving. Noticed it this morning pulling up at work. Only seems to be the driver side one doing it. Is there a way of testing if the valve is sticking closed/ not actuating properly? I had a Porsche with a similar exhaust previously and you could look into the tailpipe whilst clicking the exhaust button to see the valves open/ close. Is this possible with the C63 system, or are they concealed?

Thanks,
 
Do you have a C63 or C63S?

If its the former you only have a single valve, which is in the central pipe and therefore impossible to see. The news isn't much better with the S either though, i'm pretty sure the additional valves are located beyond the first bend in the tail pipes, so also impossible to observe. If you have a valve stuck closed, it would generally manifest itself with a loss of power under acceleration - but you wouldn't necessarily get a warning on the dashboard (so i've read).
 
Do you have a C63 or C63S?

If its the former you only have a single valve, which is in the central pipe and therefore impossible to see. The news isn't much better with the S either though, i'm pretty sure the additional valves are located beyond the first bend in the tail pipes, so also impossible to observe. If you have a valve stuck closed, it would generally manifest itself with a loss of power under acceleration - but you wouldn't necessarily get a warning on the dashboard (so i've read).
Thanks mate! Really helpful response. Yes it is a non-S model w205. Didn't realise there would be any difference between the S and non-S exhaust systems - is there a link to anything on it?... No loss of power or sound in fairness - still very loud, but with a squeak just after blipping the pedal.

Cheers
 
Thanks mate! Really helpful response. Yes it is a non-S model w205. Didn't realise there would be any difference between the S and non-S exhaust systems - is there a link to anything on it?... No loss of power or sound in fairness - still very loud, but with a squeak just after blipping the pedal.

Cheers
Actually i've given you duff info there. What I should have said was, the additional valves are present only in the 'Switchable' exhaust system, which was/is optional on both S and non-S cars - so if you have the button on the centre console, you will have the additional valves. However, it still doesn't help you very much in seeing them actuate by looking down the pipes.

This may be pie in the sky but, you might be able to see the motor link pins/wires moving (or not) when you press the button, but you'd obviously need another person under/in the car to assist with that.

Sounds like one of the butterflies might need some lube, hoping someone with more mechanical knowledge that I comes along shortly! :)
 
This picture gives a good idea of where the secondary valves are on the switchable exhaust:

1643717206334.png
 
Thanks mate! Really helpful response. Yes it is a non-S model w205. Didn't realise there would be any difference between the S and non-S exhaust systems - is there a link to anything on it?... No loss of power or sound in fairness - still very loud, but with a squeak just after blipping the pedal.

Cheers
If you have the exhaust button in your car you will have 3 valves! One located roughly under rear seats and 1 on each back box

If you don’t have the exhaust button to you will only have the one under the rear seats. If you think it’s squeaking get “exhaust valve simulator” and have it open all the time (I have it and it’s honestly the best cheap modification you can do) when driving around in Comfort you have a nice deep roar don’t need to be in Sport+ to hear the car. But it’s not stupid load just a nice deep roar how the car should have been from factory
 
Thanks both. Mine has the exhaust button so has three valves I guess. Makes sense as it sounds to be only the driver side squeaking. I have the Individual driving mode set with exhaust button on so I guess that is the same as having the 'exhaust valve simulator'?

Thanks
 
Thanks both. Mine has the exhaust button so has three valves I guess. Makes sense as it sounds to be only the driver side squeaking. I have the Individual driving mode set with exhaust button on so I guess that is the same as having the 'exhaust valve simulator'?

Thanks
I remember reading a article that even with the exhaust button on its like 50% or 70% open and when your driving full throttle above 3000 rpm then they fully open. The exhaust valve simulator has them open 100%.

When you unplug the exhaust valves they open up fully (they are normally open it needs power (signal) to close them), but without plugging that exhaust loom into something it will throw a check engline light and put the car into limp home mode.

To be honest I wouldn’t do this mod if I had the exhaust button as after this mod the button will no longer work (it’s all reservable but it would annoy me having a button that does nothing 😂)
 
Apologies for bumping an old thread, but I've also noticed that the exhaust valves squeak when I start the car with the performance exhaust on and whilst driving. Is there a fix for this? I have sprayed the silencer valves with WD40 but if there's a further valve in the mid section I'm not sure I can access it?
 
Apologies for bumping an old thread, but I've also noticed that the exhaust valves squeak when I start the car with the performance exhaust on and whilst driving. Is there a fix for this? I have sprayed the silencer valves with WD40 but if there's a further valve in the mid section I'm not sure I can access it?
When you say the valves squeak when you start the car, are you sure it isn’t the starter?
 
When you say the valves squeak when you start the car, are you sure it isn’t the starter?
Sorry for the delay in replying. I've been looking into it more. It's not the exhaust valves, I think it's a belt, pulley or tensioner as the car is making a squeaking noise when cold, which goes away when it's completely warmed up, but even when it's warm, if the stop start is on, there's a very brief chirp or squeak when the engine starts or stops. I'll book it into my local specialist next week to check.
 
Sorry for the delay in replying. I've been looking into it more. It's not the exhaust valves, I think it's a belt, pulley or tensioner as the car is making a squeaking noise when cold, which goes away when it's completely warmed up, but even when it's warm, if the stop start is on, there's a very brief chirp or squeak when the engine starts or stops. I'll book it into my local specialist next week to check.
No problem. The reason I suggested the starter was because I had a very similar noise on my previous car (2017 C63S) which had very similar symptoms. It turned out to be the starter motor bendix which had dried out. The indy I use removed it, relubricated everything and refitted and the noise stopped.
 
No problem. The reason I suggested the starter was because I had a very similar noise on my previous car (2017 C63S) which had very similar symptoms. It turned out to be the starter motor bendix which had dried out. The indy I use removed it, relubricated everything and refitted and the noise stopped.
Interesting, thanks. My car has done 86k (2015 C63 estate) so I imagine a few components will be wearing and drying out now. Hopefully it's nothing too serious.
 
Turns out the squeaking is the centre exhaust valve, but one of the belts is also a little dry but it's not an issue. When the exhaust button is on, the centre valve squeaks after you rev it. Does anyone have a fix to this apart from buying a mod box to keep it open or unplug the valve?
 

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