db2001

Hello, my E350 was at the dealership for the fuel system warranty work (the timing of receiving the letter from MB couldn't have been better). While in the shop, the dealership indicated they ran diagnostics and indicated that one of the internal plastic louvers / flaps had cracked or broken. I don't have all of the details at this point and are suggesting a repair (for $1600) or replace (for $1700). The dealer indicated that if the flap breaks off it could be "catastropic" to the engine - but quickly followed with they have never seen that happen. They also said that the mainifold is not currently throwing any check engine lights. So:
- Can I hold off on replacing the mainifold until the check engine light comes on?
- $1700 seems high. Brief internet research indicates $500 for the mainifold and 3 - 4 hours to replace. What should this cost?
- I have toyed with doing this myself. There are a couple of really good videos on youtube, but feel the sheer number of layers of connecting pieces is a bit daunting. Anyone do it themselves?

Any thoughts would be much appreciated.

LexBrett2

Are you saying that the intake manifold gasket is leaking?
Or is it another plastic part?
It sounds like the worst thing that could happen would that there would be an air leak causing a lean mixture and setting off check engine light code P0171.
I do not understand how that would be catastrophic?
Why would you need to replace the entire manifold?
Surely they would charge much, much more for that work.
Can you identify the exact part number on a diagram that is broken, so we can help you better??

db2001

See responses below -

Are you saying that the intake manifold gasket is leaking? - No leak, there is a "flap" that is stuck in the open position that leads to one of the 6 cylinders.
Or is it another plastic part? - My understanding is that the internal "flaps" are plastic.
It sounds like the worst thing that could happen would that there would be an air leak causing a lean mixture and setting off check engine light code P0171. - Maybe so, but was concerned that if a piece of the flap "broke off" (which would be a candidate for worse design ever) it could create problems for the engine internals.
I do not understand how that would be catastrophic? - See above
Why would you need to replace the entire manifold? - Flap stuck in open position
Surely they would charge much, much more for that work. - Not sure, seems to be about 900 for part 800 for labor.
Can you identify the exact part number on a diagram that is broken, so we can help you better?? - included a few good links: and
Now that I have been told that this is a likely a plastic flap that is "stuck" in the open position, presumably by 10 years of carbon build up and am not in any immediate danger, I was wondering if I took off the carb on the rear and sprayed some kind of "gentle" cleaner into the manifold and / or was able to insert a rag to wipe things down (likely no room but what if) could I resolve this issue and help against future issues.... just wondering if anyone has attempted any proactive / reactive maintenance on the manifold.

cetialpha5

There are many threads that cover this. I think it's Pierburg that was the OEM for the manifold. If you search around, you can probably find it for around $450+, I think FCP Euro has it for $455 and they have a lifetime warranty on all the parts they sell. The real MB part is about $856 but online you can find it for around $600. I'd just get thei Pierburg. I think others have said you can just replace the lever. Some say you have to take the whole intake apart to do that which also requires new gaskets and other parts, but someone else seemd to say you could get at it without doing all that. There are many youtube videos on people taking part the intake. This basically applies to all M272 engines which were used in many different cars including C class, M class etc.

How many miles are on the car? If you're planning on keeping it for the long term, I'd just replace the manifold. The flaps control runners that change the length of the intake runners so that it's tuned for low and high rpms. When the lever breaks, depending on position, either it will be fine at low or high rpm but will be rough in the other. If the mileage is low or you're planning on getting rid of it soon, then see if you can find someone that can just do the lever without taking the manifold off, someone claimed a mechanic did that and charged him less than $100. The repair kit ranges anywhere from $40-$100 depending on how many parts you need. The reason you want a new manifold if you're going to keep it a while is that the flaps inside get covered up with gunk that you can't really clean even when you take it apart. When they become difficult to move, they may snap the rods.

FCPEuro

I offer a kit with everything needed for $465 if you wish to tackle this yourself.

--Kyle

Racin_fool

Another reason to replace the entire intake manifold versus repairing the actuator and lever on the front of the original used intake, is that after replacing MANY of these intakes over the years I have also seen the plastic bushings for the swirl flaps, in the intake ports, come loose or break apart and cause cylinder head and valve damage. It's not common to see this, but i have had to replace about 6 cylinder heads because of these plastic bushings being eaten by the engine or holding the valves open and leading to damage.