Mercedes Intake Manifold Failure – Diagnosis and Repair

They don’t make them like they used to. Although overused by now, this phrase is definitely fitting when you look at some modern Mercedes Benz vehicles. This brand has retained its status as a premium manufacturer, but they, just like most automotive industries, started cutting corners about a decade or so ago. As a result, many loyal customers were left with what is now known as the Mercedes intake manifold failure issue. Our goal today is to explain what causes this annoying issue, how to diagnose it, and finally, how to fix it by yourself.

Mercedes Benz Intake Manifold Failure – the Source

Variable intakes are nothing new nor unique to Mercedes Benz. Many other brands have been using similar technologies for decades. Coincidentally, most of them had similar issues. Before we dig deeper into that subject, we need to set the stage. More specifically, we need to understand how the intake manifold on the affected M272 and M273 Mercedes engines (among others) works.

Intake Manifold Gasket - Driver Side
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Timing Air Turbulence

Air is an absolutely essential part of combustion and hence the overall operation of any internal combustion engine. However, just getting air in there isn’t enough. Over time, engineers have found that timing the moment when the air reaches the intake valves can significantly improve several performance parameters of an engine. You can get better power in the lower RPM range, better fuel economy, overall better efficiency, and more.

The way Mercedes has achieved variable intake timing is by using short and long runners. An intake runner is a tube that leads air from the intake port to the cylinder head. As the intake valve closes, the air going into the engine hits the back of the valve and is diverted back up the runners into the manifold. In a perfect world, you’d want the air to come back to the intake valves just as they’re opening up. Doing so will ensure that the densest air is getting into the cylinder.

Crankcase Breather Hose - Valve Cover to Intake Manifold
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The Art of Scavenging

This is called scavenging (or Helmholtz resonance for those more scientifically inclined).
One way to do this is to lengthen or shorten the runners. If you time everything right, you can achieve the scavenging effect at different parts of the RPM range. Unfortunately, you can’t ensure scavenging across the entire RPM range. For most road cars, you’re looking at a narrow band of around 3,000 to 4,000 RPM.

The situation is different for high-performance engines, which are often tuned so that optimal scavenging happens much higher in the RPM range. Doing so ensures peak intake values when you hit the power band.

Engine Intake Manifold Kit
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Mercedes Variable Intake Manifold Design

Mercedes Benz 3.0 and 3.5-liter V6 and V8 engines (M272 and M273) are fitted with a variable intake manifold that includes a set of long and short runners. Mercedes has used a series of flaps and an actuating mechanism to bridge these runners, changing the distance air needs to travel to reach intake valves.

For whatever reason, engineers at Mercedes Benz have decided to make this entire assembly out of plastics. When we said they don’t make them like they used to, this is what we meant. Although modern composite materials are fairly durable, whatever Mercedes has used to make variable intake mechanisms isn’t all that impressive.

These parts, much like other plastics within the engine, tend to get brittle over time. Endless heat cycles, friction, and other factors will eventually push any type of plastics to the brink of its durability.

Exhaust Manifold Hardware Kit
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Symptoms and Diagnosis – Stuck Flap

As it is the case with most intake manifolds, they tend to gunk up over time. We can thank the PCV system for this particular instance, which is a fairly standard affair in these engines. That being said, once the gunk starts to build up, the swirl flap is forced to work against increased resistance.

Given enough time, the flap will reach a point where the resistance is too much. Interestingly enough, it’s not the flap that goes first, but rather the cam lever that activates it. The lever is, you’ve guessed it, made of plastics. The result is a stuck flap and an engine that has suddenly lost its ability to fine-tune intake timing.

The resulting symptoms often include loss of power, misfires, extremely rough idle, engine throwing P2006 codes, and a persistent check engine light.

Cam Lever Repair and Other Remedies

Sorting this issue comes down to replacing the entire actuating assembly. You’d think that going for an OEM part in 2020, all this time after the issue was first recognized, would ultimately save you from a headache down the line. Unfortunately, that’s not the case.

The OEM part brings just more of the same. Instead, there are repair kits that will replace all of the affected components with ones made of aluminum. Needless to say, the aluminum arm will outlast any plastic part, no matter how much of that precious Mercedes engineering went into it.

We offer quality repair kits that are designed to replace all of the problematic parts with durable replacements. All of these components meet and exceed OEM spec, so there’s nothing to worry about in terms of performance.

However, you’ll need a few more accessories aside from the kit itself. We strongly suggest that you get both the driver side intake gasket and the passenger side intake gasket. Furthermore, performing this repair is an excellent moment to swap the intake manifold bolts for a new set. Keep in mind that linked accessories are for the M272 V6. Consult our part finder tool to locate gaskets and bolts for the M273 V8.

Intake Manifold Bolt (M6x50)
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Repairing the Intake Manifold on Mercedes Benz M272 and M273 Engines

Repairing the intake manifold on these engines is a perfect DIY project for those who aren’t afraid to get their hands dirty. Just make sure to stock up on patience. We won’t go too much into detail on the replacement procedure as we’ve written a complete guide that you can check out here!

Without being redundant, we’ll address some potential issues that might come up during the repair process.
Over time, it has become apparent that cleaning the intake manifold is an essential but often overlooked part of the process. Replacing what’s broken will solve the lack of variable intake timing, but it won’t help the swirl flap move freely again.

Therefore, you’ll have to pop the manifold and give everything a thorough cleaning. If you decide to fix the intake on your own, you probably know this. However, what you may not know is that removing the intake needs to be done with much more care than most think.

Intake Manifold Gasket - Passenger Side
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Debris Management

An average manifold is packed with crud and gunk. In some cases, it’s this crud and gunk that keep everything sealed up. What you want to be extra careful with is making sure that none of that crud falls into the engine.
Although it sounds simple, preventing debris from entering the engine is much harder than it seems. One of our readers, Mark, has suggested blowing the surrounding area with compressed air before intake removal. This way, you’ll blow away most of the potential contaminants.

In addition to this, we strongly suggest using paper towels to plug up all of the ports before blasting them with air. You might find that dry blasting works, but that WD40 is also useful at times. At least it was for our reader Mark who was kind enough to share this tip with us. We’ll attach his message at the bottom of the article for reference.

Mercedes Benz Intake Manifold Failure - the Source

How to Prevent Crud and Gunk from Forming in the Manifold?

The main culprit and the reason why your flap is not opening freely is the PCV system. While there’s not much, you can do in terms of how this valve works, and you can help it stay clean by only using quality engine oils and ensuring that you change said oil on time.

We strongly recommend Motul engine oils that match your engine code. Motul and Mercedes Benz have been working together on a line of brand-specific and general-purpose high-quality lubricants. Using Motul is an excellent way to keep any potential issues at bay.

Engine Oil Change Kit (5W-30) (7 Liter) (SYN-Nergy 6100)
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How to Find Quality Replacement Parts for your Mercedes Benz?

Here at, we take great pride in being one of the premier suppliers of genuine parts for various European vehicle brands. Mercedes Benz is right there with other core brands. To find parts that fit your Mercedes, simply select your vehicle’s make, model, and year over at our online store. Our system will give you a complete list of parts that match and more!

In case you have any questions regarding the availability of parts, or whether they fit your specific vehicle, feel free to get in touch with us. You can reach us via email or by giving us a call. We’re standing at your service and will offer assistance with whatever question you have!

Lastly, here’s Mark’s message:

“I do have to point out one major problem I found that was totally disregarded in any of the numerous written and video tutorials about pulling and replacing the Mercedes intake manifold (All were otherwise extremely helpful) and that has to do with dirt and grime falling into the intake ports during the removal of the manifold. No matter how much you try to keep things clean, I believe the layout makes it impossible to keep engine crud from falling in there. And I’m talking small sand and pebbles included. A disaster waiting to happen if not removed. I had been vacuuming all around the engine before and after I pulled the manifold, but the vacuum would not get anything out from the ports and on the valves. I found that works were to take an air gun, stick it way in, and blast around each valve numerous times, both dry and with some WD40 sprayed in there.

Make sure you have a wad of paper towel stuffed in each other port that you are not blasting and keep another big wad in your other hand positioned right over the port that you are blasting to catch most of the stuff that comes out, especially when blasting after spraying the WD40. It can be a total mess otherwise. Again, do this multiple times until you see that the valves and ports are totally clean. The area of concern beyond that is how clean you can get the cylinder(s) that happened to have its valves open when you pulled the manifold. I blasted that twice as much as the others. Don’t know what was actually left in there, and maybe it would have been a good idea to have pulled the spark plug, so the crud had another way to escape, but so far, the vehicle is running well. I’m hoping whatever went in was either blasted out or pushed out the exhaust by now. Fingers crossed.

The result of fixing the Mercedes Benz intake manifold problem and replacing its coils and spark plugs is a vehicle that idles smoother than it ever did (50.k miles since bought) and so far runs excellent. Thanks again for your help. I hope my experience here helps someone else as they come across the same situation.”

Thanks, Mark!

64 thoughts on “Mercedes Intake Manifold Failure – Diagnosis and Repair
  1. Alexander Aguirre

    Hello, I am actually living in Slidell, Lousiana, and I have this same problem. I would like to repair may car but tell me please if you have any office or mechanics near me

  2. Morris

    I’m interested in the pierburg manifold. I’m concerned that updating to the aluminum control lever could create a new weakest point, one that could cause far worse damage. Much like junk BMW manifold flaps eat expensive engines..

    • Adam Goral

      We have a few of these style intake manifolds in stock, based on engine size. Shortly after writing this article, a V8 version showed up to the warehouse as well. Pierberg is the OES manufacturer for Mercedes Benz.

    • Adam Goral

      We have two options for you, the first is a repair kit that will only fix the fault that has to do with a weak point outlined in this article. The kit part number is 103E00001 and is superior to others due to all metal construction. The second option, if there is a failure elsewhere in the manifold, or the manifold is too gummed up to continue using, is a new one. We carry the Pierburg part direct from the manufacturer, which is the Genuine Mercedes-Benz supplier. That means you will be getting an OEM part for a fraction of the price of Genuine. That part number is 2721402401. Labor prices vary far too much to be able to accurately quote here. Hope that helps, Janet.

  3. Randall

    Are there instructions online somewhere that show the necessary steps to install the little metal actuator arm? I have read that the manifold must be removed in order to do the fix. You say it’s something a beginner DIY person could do?

  4. Stephen Mras

    Hello Adam. we experienced this problem on my wife’s 2007 SLK 280. I ordered the metal actuator repair kit and did the install myself. Not that hard of a job. However, the engine is now throwing codes for random misfiring in cylinders 1, 2 and 3. It runs rough at idle.

    I took it to our independent Mercedes mechanic and showed him photos of my repair. He shook his head and said that the plastic cam actuator breaks because the tumbler flap rail warps. Virtually every time he sees someone try to replace the plastic cam actuator, it comes back with misfires because the tumbler flaps are warped. He said the only fix for the problem is to replace the entire manifold. I’d like to hear your comments on this. The car has right at 100K miles on it.

    Plastic parts such as the MAF and one of the vacuum line fittings broke while trying to get the manifold out. Everything is brittle at this age.

    • Adam Goral

      Hi Stephen, thanks for the heads up on the brittle pieces, I will revise the article to help future DIY’ers keep an eye out for these components. As for the repair kit, it’s not a sure fire fix because, as you pointed out (and I mentioned in the article), the cam lever snaps with the help of added resistance. That resistance is most likely the result of age and the amount of gunk that builds up from the PCV system dumping sticky oily air into the intake. Some users will only find solace after replacing the entire manifold.

      It may be possible that these extra codes are the result of the car adapting to the broken components, then suddenly being far out of calibration after installation of the fix. You may want to try and reset the ECU to allow the computer to relearn with the new hardware. If that doesn’t work, it might be time for a new intake manifold. Sorry we don’t have better option at this time, good luck with this complicated fix.

      • Stephen Mras

        Adam, what are the two smaller vacuum actuators for? They’re located either side of the larger vacuum actuator that works the cam I replaced. Some thoughts from people elsewhere that one of these is not working, thus one bank of cylinders is misfiring. However, they were not involved in the repair.

        Some posts on the internet came up in searches suggesting that the manifolds can be cleaned, but it’s a lengthy job with estimates ranging from 8 to 12 hours.

        Next question, does the new manifold come with everything on it? Sensors at the back? Hose and fittings?

    • James

      Yes you must replace the entire manifold with new, by replacing the actuator arm only, you treating the symptom, not the problem. You also run the risk of a peice breaking off and bending a valve

  5. DavidN

    Hi Adam,
    Thanks very much for the article. MBZ dealer told me that my 2008 E350 “intake manifold tumble flag code broken (my mileage is 120K, so I believe that diagnostic!). You are absolutely right for the sky rocked part price. It looks like I have to replace the metal arm too, not just the kits? I do concern with metal part that could provide more “mystery resistance” due to extra weight (Stephen comments). Please advice the parts need to purchase (i.e. 103E0001 or 2721402401 (whole assembly??? I think I will need manifold gasket too?). 5/2/2016

  6. Thomas Santiago

    My wife’s ML 350 just started doing the same thing at 147,000 miles. I was told by a Mercedes-Benz dealer that the only people that sell OEM Mercedes parts is through Mercedes dealers can you please explain to me how you are able to buy OEM parts for Mercedes Benz directly. If so how much is the the whole manifold with all the hoses and wiring harness if there’s any needed.

    • Adam Goral

      We source our genuine parts wholesale through authorized Mercedes-Benz dealers to ensure you get the highest quality parts without the dealer cost. In reference to your specific problem, please send an email to with your VIN and we will find you exactly what you need using our authorized dealer software

  7. Larry

    I ordered the part from you guys and we were attempting today to install the arm but are there special tools that we need? We didnt seem to have the tools needed to take out the manifold.

  8. Jon Simpson

    Hi there, I have a 2013 glk 350 with these exact symptoms. The engine code flogs as well as poor idle and performance intermittently and misfire codes. Definitely has the symptoms of intake manifold or vacuum leak. Does the 2013 glk 350 also suffer from these symptoms? Is the intake manifold the same? Hoping that I have narrowed down my problem to this fix!

    • Adam Goral

      Hi Jon, in 2013 the GLK received a completely new engine, the M276. This engine implements many new design features that make it unrelated to the M272 and M273 engines featured in this article. If you are experiencing performance issues related to misfires on a vehicle this new, I would lean to ignition coils and spark plugs. What CEL code are you getting?

  9. Jon Simpson

    I’m currently getting: P0300 p0301 p0302 p0303 p2188. Cylinders 1-3 misfiring as well as bank one mixture too rich. I put injector cleaner as well as high octane fuel in, also had no reading from the O2 sensor so I replaced that at the same time. Seems to have helped a little but the engine light comes back intermittently. Car will be driving fine, no symptoms, lots of power, no problems, then I’ll have an engine light flashing all of the sudden with reduced power and misfire as well as mixture too rich bank one. All of the cylinders that are missing are also bank one. My thoughts are that a sensor is getting a faulty reading or there’s a vacuum leak causing the random issue and kicking the car into limp mode. Trying to figure out what is becoming a nightmare. Would a faulty maf cause this? Car has only 50,000 kilometers..

    • Adam Goral

      I think you are on the right track with the MAF and vacuum leaks, but it is still puzzling since the car is so new, which is still why I am still leaning towards an ignition problem. Check all your air intake pipes and hoses by bending and flexing them to make sure there is no crack letting unmetered air getting in behind the mass airflow sensor, and change your spark plugs. A can of MAF cleaner never hurt, but I have never seen it fix a problem like that. With that said, the intake manifold IS still a variable runner length adjustable unit so we can’t rule it out, especially given the track record. Another thing to keep in mind is that the engine is direct injection, so you are also susceptible to intake valve sludge. Both VWs and BMWs with direct injection require regular service to clean the intake from the crud and buildup that can severely reduce performance. If your MAF is good, coils and plugs are good, there are no air leaks, and your intake ports are clean…I would take it to a dealer to have them run a computer diagnostic. Hurts, I know.

  10. The author is correct about having to replace the entire intake manifold in many cases.
    I suppose one could replace the front vacuum actuated pivot arm with the upgrade part without removing the intake bit that would require removing the secondary air pump and cutting out the engine lift eye in front of the intake which I would not recommend.
    Replacing the intake is a rewarding job and it’s like a puzzle where all the pieces fit perfectly when done correctly.
    The down side to the job are the insanely pathetic design of the intake gaskets and the provisions where they are supposed to snap on to the intake.
    If the little nubs on the intake had a notched ridge where the tabs could snap into when pressed in one wouldn’t have to tie them with string or fishing line to hold them in place.
    They are easily bumped off kilter when installing the intake while fighting to plug in that center vaccum line under the middle vacuum element.
    I messed one up and had a cyl 1 misfire and heard air squealing by the gasket when shut engine off.
    Removed intake and found my gasket bent near cyl -1.
    Put new gaskets and took a more careful approach reinstalling and it worked fine this time.
    Make sure you get a vacuum cleaner and suck out all debris under intake and look for plastic connector pieces and zip ties that may have fallen during work.
    Vacuum out all holes near valves and inspect them all with a flashlight so no grit, sand or plastic chunks are in there because they (will) get in there.
    Torque spec on intake bolts
    Is 9Nm which converts to 79.66 in lb.
    Torque bolts starting in middle and cross cross towards outside.
    I check torque once more to allow for bolt stretch.
    Usually misfires after this repair is due to improper gasket seal.
    I would like to see someone come up with some sort of holding tool that can go inside the bolt holes of intake and snap with a beveled/split ledge that could hold gasket and act as a guide for bolt holes at same time then once intake is set down it will be seated positively and you just pull the beveled guides out of the bolt holes and insert each bolt a couple threads one at a time until they’re all in….then torque.
    I currently hold my gaskets in place with fishing string and cut the strings and add bolts a couple threads one by one until they’re all in but I have still messed up gaskets even with this method….it really needs a locking guide tool that removes easily once set.
    Author please email me if you’d like to see a drawing I made of one.

    • James Schaedler

      Could we just cut the tops off the old intake manifold bolts, screw them into the threads on the heads, and drop the gaskets on to them, and lower the intake on top of the gaskets. Would that be sufficient enough to hold the gaskets in place, then install the new bolts one at a time

      • Adam Goral

        Although definitely a lot of extra work, this is a great idea and I may try it myself with other applications that have squirmy, difficult gaskets (such as valve cover gaskets)

  11. Brian

    I have a 2012 GL350 Bluetek that was just diagnosed with an intake manifold linkage sticking. They are recommending replacing both intake ports. The dealership said it was a major repair but didn’t give us an actual estimate. Is this the same issue you are talking about here? Thoughts on repair and cost? Thanks

    • Adam Goral

      Hi Brian, bad news. Although a very different engine, it is the same generation as the manifold described in this blog and unfortunately suffers from the same fatal flaws in design philosophy. The OM642 engine does have a type of variable intake port, although the design and function is quite different (diesels generally share little common ground with their gasoline counterpart). I suppose what the dealer is describing is the linkage that connects these ports together on the manifold, and more specifically the moving parts attached on the inside of the manifold. I included a photo of what the manifold looks like off of the car, part number 6420905437.

      Bluetec Intake Manifold Linkage

      You can see, much like the gasoline manifold, the actuators are thin and plastic (and actually live inches away from an exhaust gas cooler for the EGR system, so thin, plastic, and hot). This engine has the added disadvantage of having direct injection, which by design will dump hot oil vapor into your intake manifold without the cleaning properties of gasoline spraying onto the ports. The result is a severely crudded up intake port, and associated moving parts that will eventually get too gummed up to move, requiring mandatory replacement every so often, as dealers tend to love. My guess is they will charge you well over $1000, possibly in the $1500-2000 range to replace both manifolds. They are probably hoping to buy a new leather couch for the lobby. You CAN replace these yourself, but it is a complete mess and a nightmare due to the way they put the engine bay together (again, making sure these are serviced by the dealer), but we have the part and you can see it here. No photo yet because I just built this but hopefully the price is closer to reality for you, and you might be able to find an independent Mercedes specialist that can do this in his sleep due to high volume of customers just like you. Hope that is helpful!

  12. Jon Simpson

    Well the dealer has run diagnoses of the following.. Compression test along with ignition testing, smoke test to check for vacuum leaks, new valve covers and gaskets, sensors tested with no issues and they cannot seem to come up with a solution. They are saying now they think maybe a timing chain jump or similar issue, or possible something to do with intake. They are saying now that it could take hours of engine disassembly to actually find the issue and have quoted a new engine at 40 grand. Obviously not going to take this route as I feel that there has to be something being missed.

    To add to my previous comments, I’ve also noticed now that the problem never happens under load, but always seems to be when I take my foot off of the gas from accelerating. So it seems to be once I take load off that something gets triggered or malfunctions to flog the engine light. I timing chain issue would like throw different codes as well as cause a rough idle and a more consistent problem as apposed to this one being intermittent. It brings me back to an intake manifold issue as it’s on one bank of cylinders. I’m sure the new engine still has the same style intake manifold would it not? Therefore a broken flap isn’t completely out of the question. Too bad the car is out of warranty!

    • Adam Goral

      Jon, I am surprised that the engine is out of warranty being only 3 years old, how many miles does it have on it? The fact that they couldn’t figure it out, replaced your valve covers, then quoted you for a new engine makes me question this dealer’s ability. If I were you I would contact Mercedes-Benz itself and hope for some good will on their very new very expensive product.

      The intake manifold sounds to be the likely culprit, but often my experience with these matters yields something totally out of left field to be the actual cause, like a problem with the secondary air pump or a bad tank of fuel damaging the fuel system. If MB doesn’t help you out with this problem, I would search for a reputable independent mechanic. Let us know what your problem is when you find it, sorry we couldn’t be more help.

  13. Steven A Antico

    Hello Adam. I see you have helped many people. It’s so wonderful to see people that truly care!

    I have a 2007 GL450 that just started coding Intake Manifold and Thermostat. Station repairman was able to take the plastic cover off the engine and show me what was broken. I have not seen my issue listed here, but so many others have similar cases. Is this a situation that can be repaired or does the entire manifold need to be replaced?

    Thanks for any input.


    • Adam Goral

      Hi Steven, thanks for the kind words. I try to help any way I can, and I am glad people can find the eEuro blog easily and be educated and inspired for the sake of our vehicles (and sanity). Could you possibly snap a picture of your broken piece, or send a link of other people with the same problem? Even though you have the V8, the intake manifold on your car is simply a scaled up version of the V6 manifold, which also suffers the same issues with runner flap hangups and snapped plastic pieces. Here is the link to the manifold and you can easily see the similarities Let me know what part on it is actually broken and I can see if we can replace it. I am assuming you will need an entire new manifold, because the most likely cause of failure is that the manifold is gummed up, caused a lot of resistance on the flaps, and part of it broke.

  14. erik

    So, I have a 2006 ML350 and I just replaced the intake manifold yesterday and when I started it up I felt a light shaking at lower rpms and idle. when I got on the road it went away. Any thoughts as to what this could be?

    • Adam Goral

      Hi Erik, when the manifold was off was the throttle body cleaned? If you had to replace the intake manifold, chances are the throttle body is a little gummed up too. Did you have a good look at the intake valves? They could also have some buildup on them that could use a cleaning, just a guess. Another possible scenario is that your ECU had adapted to the broken manifold best it could, and now with a fresh one it is using out of date parameters. Use good fuel and give it a couple days. If it doesn’t smooth out check your engine mounts as they were probably stressed out with your poorly running engine.

    • Adam Goral

      The likely failure of the valves is due to the internal parts of the manifold being both old and brittle, as well as gummed up due to gunk buildup on the various moving components, causing them to hang up and stick (and eventually break). If he is giving you a great deal, then you can give it a try. I suspect you will be back in the shop quickly with other manifold problems. I highly suggest replacing the entire manifold and never having to deal with it again (or repeatedly pay for his labor), our price is the best on the internet for the kit, and the part is Genuine Mercedes, not aftermarket. Mercedes ML350 Intake Manifold Kit – $556.97

  15. Rod

    Hello. Ok, just got a repair quote from the dealer on my 2006 E350. I knew the transmission valve body needed to be replaced, but also got this little love note:

    Intake Manifold Replacement: FAULT CODE 0521 TUMBLE FLAP. ADJUSTER RODS FOR FLAP

    INTAKE MANIFOLD $1,348.50
    GASKET $4.24
    GASKET $4.24
    SCREW $38.32
    Total with labor: $1,923.30

    What repair kit do I need to do this myself?


    • Adam Goral

      Here is our kit that will fit that car, a substantial savings over that $1300 unit! This is the same part they would install so you can be sure the quality is OEM. They’re lovingly referred to as ‘stealerships’ for a reason. It’s not an easy DIY, a lot has to come apart to fix it, but if you were to take that kit to a local Mercedes mechanic, you are still fit to save a few hundred dollars. You may find detailed instructions here, complete with torque specs if you DO want to try it yourself. You will need some special sockets and a torque wrench if you plan on it, however.

      • Rod

        Hello Adam

        Thank you for the quick reply! That kit is what I was looking at earlier. So it sounds like you are saying I need to replace the intake manifold and their isn’t a kit to repair the adjuster rods for the flap?


        • Adam Goral

          Take a look and see if there is a broken arm on the side of the manifold, mentioned in this article . You can give this a shot, but keep in mind there are two reasons this part fails. the first is that the plastic actuator lever arm is very weak. The second is because the interior of the manifold is caked in carbon buildup and crud that keeps the flaps from moving smoothly and stuff starts breaking. The aluminum arm is a great quick fix (lightyears easier than replacing the entire manifold), but the only way to really get this car back into perfect running shape is to plop a new manifold on.

  16. Julie

    Hello Adam,

    We recently took in our 2008 R350 for schedule B service which is expensive at $629, 2 days before the service my check engine light came on. The 2 codes that came up are the P2006 Intake Manifold runner control stuck closed and P0410 secondary air injection system. They want to keep my car over the weekend and check it Monday without rushing to fully diagnose the issues. I am hoping it it a solenoid of some sort but after reading this forum I am quite concerned. I was also wondering about the 2nd code, any ideas? Thank you

  17. Peter Bolitho

    Hello Adam
    I have read the previous posts and your replies with great interest and hope.
    My 2007 ML 320 CDI has been running in ‘limp mode’ (reduced power, inability to change (kick) down by accelerator and won’t rev out over around 2,800 RPM. The car has done 297,000 Kls. I can drive it Ok with steering wheel paddles, but still has significantly reduced power.
    I tool it to MB Dealer (I like your ‘stealership’ term) and they told me I had to replace the glow plugs and sender unit. Quoted $2,600 – I took it to an independent who has shown real interest in fixing the vehicle and he did the job for $1,049.00! (Aus $) Good job, but did not fix the problem. My independent guy has now scanned again and is getting code re inlet manifold. He said I could consider setting the valves open, HOWEVER he thinks the better option would be to replace the manifold.
    Do you have a genuine MB manifold for the ML 320 CDI and if so, what cost am I looking at here in Queensland Australia?

  18. Pete Gammon

    2006 ML350 – had to replace the intake manifold 10/16 due to broken throttle lever flap. Then I found out about your aluminum arm. Luckily I had purchased the replacement manifold (Piersburg – OEM to MB) that had lifetime replacement warranty, so this time around, once I receive the new (free) manifold, I’m going to replace the plastic arm with your replacement kit *before* I install the new manifold. This should provide me with the best of both worlds……a new manifold with higher quality lever flap. THANKS

  19. Scott Rowley

    Hi,i just bought a 2007 c280 w/51000 miles,a week in I get the code for intake runner stuck closed,not experiencing power loss or rough idle,too soon to tell but im guessing this will only get worse,is their anything I can do now to prolong the inevitable since it is such low mileage. An elderly couple owned this car since new and barely drove it,is the fact that it had limited use a contributing factor? I am capable of the DIY repairs but im currently repairing my fault laden BMW,any thoughts?

    • Adam Goral

      While not an official recommendation, I think Seafoam might be worth a shot. The intake runners get gummed up by PCV oil and crud being diverted back into the intake, which then sticks on all the runners and the manifold. If you don’t have a broken lever arm, you may be able to clean and unstick the runners with a product like Seaform, or something similar that can be added to the air stream. Of course taking it out and doing a more through cleaning (and adding an aluminum metal arm) would be the best way to insure you won’t have to spend the cash on a new manifold. Hope that helps, let us know what you decide.

      • Scott Rowley

        I’m glad you said seafoam
        Ive used it before with good results,i hate to have to tear into it because I was able to convince my better half that this was a great buy for a real nice car and it should be trouble free for a good long while,at any rate,i will give it the seafoam treatment this weekend and see what happens,really enjoy reading your expertise on this and I suspect ill be consulting you hopefully not soon but i guess we both know better!!!

          • Scott Rowley

            So here we are at the end of july,i never did the seafoam treatment,its just as well as i decided to just dive in and replace the actuator arm and surprise surprise it was in fact broken,the whole job took 8 hrs but i fart around alot and take breaks,i could do it in 4 hrs if i ever have to do it again,this would be a bit difficult for someone with little or no mechanical experience but overall it was not bad,got tripped up a couple times but i was excited when it started right up,smooth idle and seemingly a renewed throttle response,im looking forward to many trouble free miles.
            THANKS EEUROPARTS!!!!!!

          • Adam Goral

            Scott, this is awesome. We’re glad you could get your Mercedes back to smooooth running. May I ask, what were your hangups?

  20. Scott Rowley

    Hey Adam,in hindsight the job was pretty easy,it looks kind of daunting opening the hood and seeing wires and hoses everywhere,the first thing i disconnected was the air pump and promptly broke the clip,i thought this was setting the stage for what was to become a bad day under the hood,fortunately this would be the only one to break but it had me nervous with every next one,some dont come apart so easy and its a fine line on how much to squeeze,pull and pry. I did the repair to the manifold and started reassembly,after torqueing the maniflod bolts and making some connections it suddenly dawned on me that i had’nt connected the wire to the throttle body,pretty deflating,thought it was all gonna have to come back apart but i was able to move the MAF elbow and plug it back in,lucky break i guess,aside from that it all went pretty good.

  21. Mark

    Adam, I have a 2007 C280 with 125k miles and suddenly the car started running very roughly, so I brought it in to my local Autozone for a reading. It came back with a P0301 (Cylinder 1 misfire) and P2006 (Intake Manifold runner stuck closed). I first swapped coil 1 and 2 and went back for a re-read. Sure enough, the code followed the coil. One issue identified. But then I started poking at the intake flap arms. Without taking anything apart it looks like all that linkage is still in tack, but VERY sticky in operation. I’m actually amazed that nothing seems broken because it can be pushed, but with great resistance, and when running it will move, but it pops through and does not reach full travel. I also have a 2007 E350 wagon with 119.k miles (came out of the factory one week after the C280) and checked that linkage out as well. Smooth as silk. The wagon always did run much smoother than the C280. So my preference would be to pull the C280’s manifold and swap in the aluminum linkage, but assuming nothing is actually broken inside, is there a way to clean all or most of the crud from the flaps while the manifold is out such that I can get smooth movement again? Maybe soak in Seafoam or something like that?

    Thanks for your continued support on this issue.

    • Adam Goral

      Great input. If this were my car, I would absolutely be following the same path. Taking the manifold off and blasting it with some sort of cleaner would be a great option. Seafoam is meant to clean things just like this while the car is running, I would be interested if it helped at all. Problem is, all that crud then goes straight into your engine which is less than ideal. Personally I would take a weekend, pull the manifold, give it a nice soak in something like purple power, and see if you can free anything up. Don’t want to disrupt any of the seals and things so I would only be aggressive with something like brake cleaner to loosen the hard to reach chunks. Let us know how it goes!

  22. Mark

    Thanks for the support. I ordered the kite with the repair kit with intake gaskets. It will be a week or so before I get it, but I’ll let you know how it does. I ordered a full set of plugs and coils as well. Really hoping this will smooth out the engine. Wasn’t terrible until this happened, but not up to what I expected from this car.

  23. Mark

    Reporting back. 8 hours of carefully pulling the intake manifold, replacing the linkage and replacing the plugs and coils yesterday. The latter being the easiest of the tasks,, of course. The original flap linkage ended up being completely in tact, and as I separated the links, the culprit was immediately evident. The central pivot was hanging up on the pivot screw. The screw was dry and corroded,, restricting movement. All the other links and both flap assemblies inside the manifold were free and moving easily. Could not have asked for a better situation. I put the new pivot and screw in with the recommended blue locktite, as well as greasing each joint and all was fine.

    I do have to point out one major issue I found that was totally disregarded in any of the numerous written and video tutorials about pulling and replacing the intake manifold (All were otherwise extremely helpful) and that has to do with dirt and grime falling into the intake ports during the removal of the manifold. No matter how much you try to keep things clean, I believe the layout makes it impossible to keep engine crud from falling in there. And I’m talking small sand and pebbles included. A disaster waiting to happen if not removed. I had been vacuuming all around the engine before and after I pulled the manifold, but the vacuum would not get anything out from the ports and on the valves. What I did find that works was to take an air gun, stick it way in, and blast around each valve numerous times, both dry and with some WD40 sprayed in there. Make sure you have a wad of paper towel stuffed in each other port that you are not blasting, and keep another big wad in your other hand positioned right over the port that you are blasting to catch most of the stuff that comes out. Especially when blasting after spraying the WD40. It can be a total mess otherwise. Again, do this multiple times until you see that the valves and ports are totally clean. The area of concern beyond that is how clean can you get the cylinder(s) that happened to have it’s valves open when you pulled the manifold. I blasted that twice as much as the others. Don’t know what was actually left in there, and maybe it would have been a good idea to have pulled the spark plug so the crud had another way to escape, but so far the car is running well. I’m hoping whatever went in was either blasted out or pushed out the exhaust by now. Fingers crossed.

    The result of reviving the manifold linkage, and replacing the coils and spark plugs is a car that idles smoother than it ever did (50.k miles since bought) and so far runs great. Thanks again for your help. Hope my experience here helps someone else as they come across the same situation.

  24. chiefseol

    I have a 2006 e350 and getting codes p0410 and misfires in 4,5,6. It says secondary air injection malfunction on left bank. Secondary Air pump works and I replaced fuel injectors, spark plugs and coils and still getting this error. Car runs and drives great most of the time except if it’s cold in the morning meaning around 40 to 50 degrees then sometimes I get these codes when cold starting it. What do you think it could be? I also checked the hoses that lead from secondary air pump and everything looks good

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