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Is there a way to measure / prevent / reverse the amount of carbon build-up on the flaps? What's the mileage of the affected vehicles?
If this will eventually happen on every om642 engine, then this flap motor and manifold replacement is going to become a regular maintenance service....
 

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GL320 CDI - 2008, '04 Touareg V10 TDI, '85 Unimog U1700, '83 Mitsubishi 4WD turbodiesel PU
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Here are the part numbers for the servo motor the dealer replaced on mine:
On the motor assembly:

PIERBURG
A642 150 03 84 Q1
On the box:
A642 150 04 94

So, is THIS the M55 motor you are referring to? There is obviously a part number change from when my engine was assembled in '07 to last November when the motor was replaced. I have no way to find out just what was changed or how significant the change is or if it had anything to do with the motor drawing too much current and popping the fuse.
Neither do I know what the motor does. If it only operates as an engine brake by throttling the intake air (no throttle is EVER necessary on a compression ignition engine) then it could go away and no great loss - it may be more trouble than it is worth.:(:(
 

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power loss

the fuse that would have blown would be fuse # 104 the problem i think you will have in the future will be that the motor will have a fault for the motor being frozen. the motor only moves the flaps in the intake manifold and they build up carbon on them from the oil that is in the intake system. they get pretty stopped up with carbon and can even stop up completely
 

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GL320 CDI - 2008, '04 Touareg V10 TDI, '85 Unimog U1700, '83 Mitsubishi 4WD turbodiesel PU
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To further clarify the question of what the motor does; I know the motor (and is THIS the M55 motor?) only operates the 'flaps'. [I looked at the L intake manifold yesterday and the 'flaps' look exactly like the throttle valve in a carburetor - one at each intake air hole to each cylinder. AND there was some powdery carbon present, but not much - not like in the intake manifold of my '00 Golf TDI before I did the EGR delete] The real question I'd like an answer to is, what is the desired outcome of closing these butterfly valves and shutting off the air to each of the cylinders? What function did the engineers want to achieve?
If it is designed to prevent a runaway engine by stopping air flow in the event of a big oil leak from the turbo seal, then it is a TERRIBLE design because, if there is an oil leak there is likely to be a large amount of carbon in the intake and the butterfly valves won't close and the runaway will continue!
If it is designed to provide engine braking assist (ie compression braking) like a gas engine then it is absolutely non essential and should NEVER have been hooked up so that it couldn't be easily bypassed without 'check engine light' issues etc.
If there is another credible answer I wish someone would tell me. I'd like the whole motor/throttle valve thing to go AWAY! It has already caused an important cross country trip we had planned to be aborted.:mad:
 

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2004 E320 wagon sport, 2006 R500
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EGR delete

EGR delete sounds like a great idea, because EGR is a terrible idea.
Bugg, you're saying the carbon that builds up in the flaps come from the intake air, which comes from normal oil leakage from the turbo. Add hot exhaust from the EGR and you have carbon buildup on the intake side. All this to satisfy new car emission standards. I'd rather have MB satisfy semi-used car reliability standards.
 

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the egr valve on the engine are cooled by coolant and they are getting pretty carboned up. the flaps act like the throttle plates for a carb and are used to control rpm and fuel input. they cannot be done away with because they are they throttling mechanism for the engine. i have seen the intakes almost stopped completely up by carbon. there is a pipe that comes out of the bottle of the air pipe before the intake manifold and it is cooled also coolant and they get pretty stopped up also. i agree it is poor design but they made it i just fix it.
 

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2007 GL320 CDI, 2011 Audi S4
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I've had the same issues with LH mode/turbo leak. Had to replace a cracked plastic piece that was letting excessive oil in.

I've also replaced transmission valve body/front air shocks/turbo boost hose/liftgate latch. I'm sure I'm forgetting something. This vehicle has been an expensive PITA to maintain. If my wife didn't love it so much (when it works) she'd have a Honda Odyssey! :(
 

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GL320 CDI - 2008, '04 Touareg V10 TDI, '85 Unimog U1700, '83 Mitsubishi 4WD turbodiesel PU
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bugg464 - there is NO WAY the butterfly valves in the intake control ANY of the fuel input. ALL fuel is directly injected by the pizeo injectors. That's how a diesel works. Diesels also NEVER need to have the air restricted in any way. That's why there is never a throttle plate on a diesel. The butterfly valves in the intake manifolds are there for reasons OTHER that correct operation of the engine as a diesel.
Max Blast - there are two sources of oil that may create carbon in the intake; one is the front turbo oil seal which always passes a small amount of oil (mine uses less than a quart in 10,000 mi), the other is the crankcase vent system. According to what I have read, MB has done a remarkable job of efficiently removing a very high percentage of the oil mist particles that come out of the crankcase (CVR system). VW did not do as good a job on the CVR on the early Jetta and Golf TDIs and the result was a nearly 100% chance of crankcase vent oil mist getting carbonized by EGR gasses and completely plugging the intake manifold [ask me how I know!]. A contributing factor was those owners who decided that they could use ordinary dino 30W oil and NOT the full synthetic oils specified! Bad decision! Full synthetic oils are WAY better at handling heat and not carbonizing. If you have EGR on a diesel, you really need the synthetics.

The very next time I get 'into' the engine on my CDI, I'm going to disconnect the linkage from the servo motor to the butterfly valves. The valves will be parked in the open position. When that happens, I'll let you know the results, if any.
 

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Being the less than proud owner of a new turbo inlet motor purchased out of warranty (88000 Miles) I was wondering what the Mercedes book calls out in flat rate hours to replace the fine motor. My dealer stuck me for 9.6 hours.... I was also told to be grateful as most of the time when this part fails, the Linkages and associated butterflies break when trying to free them up and the entire intake manifold has to be replaced.

Anybody else seen the flat rate hours for this job?
 

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GL320 CDI - 2008, '04 Touareg V10 TDI, '85 Unimog U1700, '83 Mitsubishi 4WD turbodiesel PU
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I'll have to scan the work order the dealer charged me for the work to see the hours they claimed. I'll post later on this. I do remember that going by the list of bolts etc they 'replaced' they seemed to have re used NONE of the original German fasteners!
 

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bugg464 - there is NO WAY the butterfly valves in the intake control ANY of the fuel input. ALL fuel is directly injected by the pizeo injectors. That's how a diesel works. Diesels also NEVER need to have the air restricted in any way. That's why there is never a throttle plate on a diesel. The butterfly valves in the intake manifolds are there for reasons OTHER that correct operation of the engine as a diesel.
Max Blast - there are two sources of oil that may create carbon in the intake; one is the front turbo oil seal which always passes a small amount of oil (mine uses less than a quart in 10,000 mi), the other is the crankcase vent system. According to what I have read, MB has done a remarkable job of efficiently removing a very high percentage of the oil mist particles that come out of the crankcase (CVR system). VW did not do as good a job on the CVR on the early Jetta and Golf TDIs and the result was a nearly 100% chance of crankcase vent oil mist getting carbonized by EGR gasses and completely plugging the intake manifold [ask me how I know!]. A contributing factor was those owners who decided that they could use ordinary dino 30W oil and NOT the full synthetic oils specified! Bad decision! Full synthetic oils are WAY better at handling heat and not carbonizing. If you have EGR on a diesel, you really need the synthetics.

The very next time I get 'into' the engine on my CDI, I'm going to disconnect the linkage from the servo motor to the butterfly valves. The valves will be parked in the open position. When that happens, I'll let you know the results, if any.
I wonder if you will get a CODE and LH mode? I agree with you regarding the needless flaps. Is there an 'easy' way to clean them, just for preventive maint?
I already told my wife that my next hauler will be a Ford Flex.
 

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No easy way. The intake manifold (s) must be removed. To do that, virtually everything on the top of the engine must come off (except turbo)! There are several bolts the dealer replaced which I'm not sure are 'stretch bolts' [ie one time use] or not. If they are "torque to a value then turn x degrees" stretch bolts that adds to the complexity since the torque value must be known to reinstall.:mad::mad: A REALLY DUMB DESIGN!
 

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the turbo has to come off to take off the manifolds and all the bolts they ae replacing are stretch bolts. the flaps are there to produce boost acoording to mercds benz. i am a technician and if the light is on it will have a code for the m55 shut off motor. to remove the manifolds you hav to drain the cooling system, remove turbo, egr valve, ful filter cage oil feed for turbo charger.
 

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2016 AMG GLA45 Black, 2010 E500 Cabriolet - Tenorite gray/Black Interior, Distronic Plus
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It sounds like everyone is convinced they know what the problem is but my GL500 (I realise this one is a diesel) had a similar issue caused by a bad transmission turbine speed sensor. No check engine lights, no reverse and a restart fixed it every time - for a while.
 

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the turbo has to come off to take off the manifolds and all the bolts they ae replacing are stretch bolts. the flaps are there to produce boost acoording to mercds benz. i am a technician and if the light is on it will have a code for the m55 shut off motor. to remove the manifolds you hav to drain the cooling system, remove turbo, egr valve, ful filter cage oil feed for turbo charger.
I'd be VERY interested in finding out just HOW the throttles in the intake (they call them 'flaps') produce ANY boost or assist the turbo in producing boost! I think it is M-B BS!:eek:
 

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I have a 2009 GL320 Bluetech and have had the same issue. Driving down the freeway and the car wont go above 60mph, downshifts are rough, if you slow down, it takes forever to get back upto 60mph. It has happened 5-6 times and each time, if I pull over and restart, all is well.

Went to the dealer 3 times. each time he couldnt reproduce the problem and that there were do codes for him to diagnose with. It has only happened when I am away from home so havent had the chance to take it home in "limp Mode".

We should communicate these issue to MBUSA. Looks like it is a common problem with the bluetech turbo.
 

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SAME Blutech Turbo power loss problem here too

I have a 2011 E350 BluTec Turbo. Exact same issue, I get a power loss condition after driving a half hour+ on occasion. Transmission holds on to gears way too long, has a hard time accelerating at all - on the freeway I can maintain speed as long as there's no incline coming up. turning the motor off and then on again resets the problem and the car drives perfect. for a while. Seriously annoying. There's no codes, dealer cannot reproduce problem at all. I actually drove my car to the dealer while it was in this low power mode. The service tech drove the car around the block and confirmed the car was having a serious power loss issue with no codes, alarms or service lights. They replaced an EGR valvle because that had a code from a previous issue when it came on one time but the car exhibited the same behavior next time I picked up the car. There is obviously a problem, but as soon as the car is turned off the dealer cannot reproduce it and there's no codes, so they wont do a damn thing for me. taken it to them a dozen times now. Can people please POST THEIR LAST 8 Digits of their VIN so we can show Mercedes this thread? right now they seem to be ignoring an issue that's affecting customers so perhaps if they see a common pattern from other Blutec owners they will figure this out and help.
 

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The carbonized intake flaps when down on me same issues. This is at least a $3k. in addition to my tranny problems, the srs going down. I traded in the 320 for a GL550.
 

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ML 55 AMG 2002 w163.174, E320 CDI SW evo W211.222
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how to do it yourself ....

V6 CDI Inlet Port Shut Off Motor Replacement - Mercedes-Benz Owners' Forums

here a post that explain how to replace M55 air intake flaps motor
oem parts for om642 april 2007 are
M55 servomotor
A6421500194 replaced from: A6421500294
A6420903237 DX mainfold air intake
A6420905437 SX mainfold air intake

they suggest to replace some gasket too
expecially the one between air ducth to intake turbocharger A6420940080
and oil vapour recover A6420160330....

seems that failure of M55 is due to 2 main reason
1) intake flaps sticked/blocked from exaust dust
2) oil leaking from gaket turbocharger where oil vapour are recovered that damage the motor

in the second case is probably possible to avoid to change air intake collectors.... of course is mandatory to fix oil leaking...
i hope to be in this "lucky" situiation.
 
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