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My E350 (2008) just passed the 100K km mark and i wonder what to do with the well known intake manifold problem. currently there is no sign of any problem but I prefer preventive maintenance instead of running to shop when it happened (and usually it would happen in the most inconvenient time...). I'm going to pull out the intake manifold probably in the coming month and replacing the plastic lever in the center with the aluminum replacement and I'd like to ask a few equations.
-Where to buy the aluminum replacement?
-Should I need to replace the intake manifold rubber gasket?
-Is it possible/a good idea to disintegrate intake manifold and clean the flaps manually with cleaning spray?
-Is there any else to do while i fix the intake manifold?
replace hardware for manifold to cylinder head (stretch bolts) magnesium to be exact. Injector o-rings, and metal gaskets. If you're going to clean throttle bottle i advise you get a new gasket for that as well. For tumble flaps just ebay search m272 tumble flaps/repair kit. IF you're feeling real froggy you could separate manifold and clean it that way but dousing it in cleaner i wouldn't do personally but that's just me....
Well... the good news is the intake manifold got out (after 2 hours of hard work), it seems clean and only small amount of oil is on the flaps.
The bad news is the screw holding the plastic was broken inside when we tried opening it!
You mean use one of the available intake cleaner aerosols? Do you think they are a bad idea?
Don't bother. Just replace the oil separator and breather cover on the passenger side. When those go bad, more oil gets into the intake and ends up coating the flaps. It will probably eventually go, but you might make it a lot longer with changing those parts regularly. I'm not sure if you really need the rest of the parts in this breather kit, you can check your hoses and the 3 plugs also but the bad plugs just mean you get oil leaks. I wouldn't replace the lever either, that's just an early warning sign that the flaps are gumming up. The metal lever just means the lever won't break and it will force the flaps to the point where they will break off and fall into the engine causing additional damage while the plastic lever will just break and the flaps won't move and then you'll get an error code telling you it's time to replace the manifold.
Also if you clean the manifold without taking it off, where do you think the debris will go? Into the engine. And if you take it off to clean it, it's pretty involved to take it off and you mind as well wait til you need a new manifold to do it.
Once the intake is compromised, i.e. enough oil to gum up the flaps, your best option is to replace it.
Now the preventative maintenance is to monitor the breather and replace it more frequently. How long? nobody knows. One thing though the next generation after the M272/M273, the M276 has a sort of oil catcher before the intake, engine intake elbow. I have removed oil from it, so adding one to the M272/M273 should not be a bad idea. Worth the return on the investment? Depends on your plans for the car long term.
Here is a crude installation of an oil catcher for the M272
Once the intake is compromised, i.e. enough oil to gum up the flaps, your best option is to replace it.
Now the preventative maintenance is to monitor the breather and replace it more frequently. How long? nobody knows. One thing though the next generation after the M272/M273, the M276 has a sort of oil catcher before the intake, engine intake elbow. I have removed oil from it, so adding one to the M272/M273 should not be a bad idea. Worth the return on the investment? Depends on your plans for the car long term.
An oil catch can is definitely a good idea and I will be installing one as well as refreshing the PCV oil separator.
But I am also thinking of planning to include some fogging on the intake as a regular maintenance item. This is not a diesel engine so the chances of big chunks of carbon landing inside the engine are low. I see more benefits than risks.
Can anyone please confirm at what engine RMP on idle do the intake flaps open/close?
My plan is to ingest some cleaner into the system at this spot after removing the breather hose. I will be using a homemade concoction sprayed with a small spray gun into this opening.
The literature mentions two switchover points for the runners, 1750 RPM for long runner and 3900 RPM for the short runner. I was thinking of rev the engine in between the two switchover points while misting the intake but 4K on the rev range is a bit higher than I am wanted to go. Maybe I will do this a few times and even with the long runner activated the hinges and outside of the flap will get misted.
The swirl flaps again get activated high up. But given their location I think they should get misted across the rev range.
If all goes well we go for a spirited drive after cleaning any codes and resetting fuel adaptations and all should be done in a weekend afternoon.
Just be careful keeping in mind @cetialpha5 suggestion. Intake/valve cleanup is usually a reverse process that is from the head towards the intake, not the other way around. If any solid debris separates from the intake walls/flaps, and they go through the intake valve your engine may fail badly. You do not know what kind of debris are coming out, and guessing they will not cause damage downstream is a wild bet than could cost you more $$$ than a new intake + installation labour + car's downtime.
I don't believe that you can get it cleaned that way. On higher rpm's air is rushing through the intake so fast that cleaning solution just doesn't have time to remove anything.
I'm not really sure the time and effort is really worth it. A new intake is about $700 plus labor. How much time and labor do you think you'll spend trying to clean it? Also you don't have to play with the RPMs that much, there's the lever that breaks and you can move that by hand if you can get at it and that will move the flaps. And the carbon you're talking about is basically baked on oil. Mine went on my other car, the lever was very stiff and it didn't bounce back when moving it by hand. New one moved easily. The W211 is still on the original intake and I'm over 130k now. Never did any cleaning. At some point it might need an intake but I'd rather just replace the intake than bother trying to clean it, might make it worse. Isn't it telling that no one else has tried to clean it? Lots of threads on here about bad intakes getting replaced. But if you do it, let us know how it goes. How would you even know if you really cleaned it?
Also some people replace that lever with a metal one and then later report that bits of the flap broke off and caused engine damage. How would you know that cleaning gummed up oil and having it fall into the engine won't do the same thing?
Last edited by cetialpha5; 01-27-2023 at 01:45 PM.
Here to report back after doing the procedure. The entire thing took less than an hour between me and my dad. Started with removing the air filter housing/cover and got to the PCV breather which I intended to loosen at the throttle end and spray there. Noticed it is help by metal clamps which I did not want to struggle with removing so decided I will take off the MAF and the intake elbow and spray directly at the throttle butterfly. We held the throttle steady at about 1500 RPM with a few blips in between. On doing the blips I did notice the engine stumble and knock a bit. Finished the spray, hosed down the MAF sensor with cleaner, blow dried it and put everything back together to take it for a drive. The tailpipes were smoking a bit and the car knocked for about a Km. I was a bit uneasy for the initial drive because of the knocking but kept a slow steady pack. After about a Km the knocking went away and I gave it a few floors to clear out any remaining cleaner from the system. Came back hooked up Xentry and noticed a few error codes. Mostly harmless stuff caused by disconnecting the MAF etc. Cleared those cods and called it a day.
Now my feedback on the results. I have a small borescope but I did not bother to use that because I did not want to add one more process to my procedure. Maybe another day. But in the evening I took to the highway and noticed that car throttle response being much much better across the rev range. My dad . The car just felt so much more eager. There was a top end push that was not there earlier. Possibly the Runners were operating a tad bit more freely and I could feel the transition.
Long and short. I will make this a part of my regular maintenance items. For me the idea is not to scrub the intake till it is spotless. I am happy if even a small amount of the cleaner is deposited on the flap hinges and mating surfaces which make the runners/flaps move a bit more freely and seal the surfaces a little bit better. Incremental improvements is what I am looking for and once done at regular intervals I hope they will keep the intake system healthier than it was.
One small note to myself. I would not blip the throttle the next time I do this procedure to avoid the knocking.
I had the same issue. The car would take longer to start and throttle was not responsive. I checked with a computer and it gave me P2004. My car is in pristine condition and under 100k mileage. The engine is as dry as it could be. Upon research, i learned the moving mechanism of the tumble flaps. I used w240 externally on the lever and cleaned it as much as i could. It worked. Turns out it was just dust and gunk that had been building up for over a decade. It’s working great but i think i will have to replace them sometime.
I had the same issue. The car would take longer to start and throttle was not responsive. I checked with a computer and it gave me P2004. My car is in pristine condition and under 100k mileage. The engine is as dry as it could be. Upon research, i learned the moving mechanism of the tumble flaps. I used w240 externally on the lever and cleaned it as much as i could. It worked. Turns out it was just dust and gunk that had been building up for over a decade. It’s working great but i think i will have to replace them sometime.
If the lever moves freely now then maybe you have some time before the flaps are really gummed up. Did you replace the oil breather cover and separator which is reverse threaded? My old intake was so gummed up that once I moved it by hand, it didn't spring back, but the new one popped right back when moving it by hand.
11-05-2016, 12:32 PM
