P2004/0521 Swirl Flap Stuck Open. Fixed but still coding!
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Joined: Feb 2020
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2011 E350 Wagon
P2004/0521 Swirl Flap Stuck Open. Fixed but still coding!
My 2011 Mercedes E class wagon at 145k miles showed the P2004 code. So, like any DIY car owner I researched the issue and found that my culprit would probably be a broken swirl flap lever arm. I looked in my engine and sure enough, I could open and close my swirl valve with one finger, and the ball portion of the lever had snapped off.
I removed the intake manifold and replaced the lever arm with this:
It has some positive reviews and I thought it would be a good choice.
After screwing it to the manifold and connecting it to the solenoid lever arm, I thought that it seemed very stiff. It had swiveled more easily before connecting it the solenoid....But I figured that was a good thing. After installation, I cleared codes and started the car. It sounded fine. So, then I went to work the next day, and as I pulled into the parking lot I saw the dang check engine light again. I checked the codes right there and then, and saw the same code. This didn't make any sense to me because my mileage was better than before and the car seemed to idle smoother.
Upon looking in the engine bay with the engine still running, I noticed that the lever arm and solenoid weren't really moving. Should my swirl valve be moving back and forth rapidly? Anybody have any idea what could be wrong now? I'm thinking that the issue is that the solenoid is busted and I need to replace it >.<
I'm sorry if this issue has been seen before. The only reason I found out that I could replace the lever arm was because of looking through this forum. But I can't find anything related to still having an issue even after replacing the lever arm. I appreciate any input.
I removed the intake manifold and replaced the lever arm with this:
It has some positive reviews and I thought it would be a good choice.
After screwing it to the manifold and connecting it to the solenoid lever arm, I thought that it seemed very stiff. It had swiveled more easily before connecting it the solenoid....But I figured that was a good thing. After installation, I cleared codes and started the car. It sounded fine. So, then I went to work the next day, and as I pulled into the parking lot I saw the dang check engine light again. I checked the codes right there and then, and saw the same code. This didn't make any sense to me because my mileage was better than before and the car seemed to idle smoother.
Upon looking in the engine bay with the engine still running, I noticed that the lever arm and solenoid weren't really moving. Should my swirl valve be moving back and forth rapidly? Anybody have any idea what could be wrong now? I'm thinking that the issue is that the solenoid is busted and I need to replace it >.<
I'm sorry if this issue has been seen before. The only reason I found out that I could replace the lever arm was because of looking through this forum. But I can't find anything related to still having an issue even after replacing the lever arm. I appreciate any input.
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Joined: Jul 2015
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From: San Diego, CA
2016 E350 Sport; Mom Wrecked the 2008 E350; sold the 2002 C320
Let me start by saying that I haven't tackled this issue on the W212 but I did do so on my previous W211. That being said, it is a little concerning that you state that the solenoid lever arm seemed very stiff. After installation, the butterfly should move rather freely. With the arms connected to the diaphragms, it should offer a little resistance but should not be too stiff. There is no rapid movement at idle - the levers operate to open and close the flaps inside the intake manifold at cold vs hot temperatures at different points of acceleration to increase or decrease the air volume in the intake manifold.
What happens many times is that when the butterfly breaks, it causes the flap rods to bind, which can eventually lead to the flaps breaking and which in turn can lead to catastrophic internal engine damage. That's why it is recommended to just replace the entire intake manifold assembly.
If you take it apart again, check the movement of the flap rods individually (with the butterfly disconnected) to make sure they are not binding.
[Edit]: I myself went with a metal butterfly on the W211 but what was explained to me by a MBZ tech is that they make the OEM ones out of plastic so that in case the flap rods start binding, the butterfly will give before the flaps break and damage the engine internals.
What happens many times is that when the butterfly breaks, it causes the flap rods to bind, which can eventually lead to the flaps breaking and which in turn can lead to catastrophic internal engine damage. That's why it is recommended to just replace the entire intake manifold assembly.
If you take it apart again, check the movement of the flap rods individually (with the butterfly disconnected) to make sure they are not binding.
[Edit]: I myself went with a metal butterfly on the W211 but what was explained to me by a MBZ tech is that they make the OEM ones out of plastic so that in case the flap rods start binding, the butterfly will give before the flaps break and damage the engine internals.
Last edited by EuroDriverSD; Feb 6, 2020 at 03:27 PM.
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From: MA
2008 E350 4Matic, 2011 E350 4matic
Yeah the proper repair is to replace the entire manifold for long term use, those repair parts are just a short term fix. It's about $580 from FCPeuro. You should also get the O rings for the injectors and the intake manifold gaskets. There are youtube videos on how to do the replacement.
https://www.fcpeuro.com/products/mer...fold-700246330
You could also search on eBay, the rods also break. They're not supposed to move rapidly. They're basically tuned intake runners. At high rpms, it switches to one set of runners and at low rpms it switch to the other. So depending on where the flaps break, you either get bad performance at high or low rpms. The flaps get gummed up over time and become difficult to move, eventually those bits break. You can replace the lever and the road, but they will continue to get gummed up and eventually break off which can cause engine damage. That's why those bits are considered a short term fix. Long term is to replace the manifold and you're good for another 100k+. You could also pick up a rebuilt one on Ebay for $350, but you have to send in the core and $580 at Fcpeuro comes with a lifetime warranty as opposed to the 1 year on eBay. Still in theory it should last a while so maybe the lifetime warranty doesn't mean anything in this case. The one from FCP is the Pierburg which is the oem maker for Mercedes.
https://www.ebay.com/itm/Mercedes-E350-2006-2011-M272-V6-Engine-Modified-Intake-Manifold-Gasket-Set/192758184793
https://www.fcpeuro.com/products/mer...fold-700246330
You could also search on eBay, the rods also break. They're not supposed to move rapidly. They're basically tuned intake runners. At high rpms, it switches to one set of runners and at low rpms it switch to the other. So depending on where the flaps break, you either get bad performance at high or low rpms. The flaps get gummed up over time and become difficult to move, eventually those bits break. You can replace the lever and the road, but they will continue to get gummed up and eventually break off which can cause engine damage. That's why those bits are considered a short term fix. Long term is to replace the manifold and you're good for another 100k+. You could also pick up a rebuilt one on Ebay for $350, but you have to send in the core and $580 at Fcpeuro comes with a lifetime warranty as opposed to the 1 year on eBay. Still in theory it should last a while so maybe the lifetime warranty doesn't mean anything in this case. The one from FCP is the Pierburg which is the oem maker for Mercedes.
https://www.ebay.com/itm/Mercedes-E350-2006-2011-M272-V6-Engine-Modified-Intake-Manifold-Gasket-Set/192758184793
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Joined: Feb 2020
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2011 E350 Wagon
Thank you both for the input. The swirl flaps moved very easily on their own, before reconnecting to the solenoid. I will take it apart this weekend after an oil change and decide if I should replace the entire manifold or not.
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Joined: Aug 2020
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From: Hyderabad, Telangana
EQC, S Class Extended, Grace CVT.
