What a surprise!.. Wife's '06 ML350 had intermittent CEL. Last year, dealer replaced cam / timing position sensors. Problem continued to occur with CEL coming on even more frequently. NOW, they tell me that the Balance Shaft has a bad gear and it is deteriorating. 73K miles. Thank goodness for extended warranties. Finding from other web site threads and blogs that MB USA is not consistent with the treatment of customers... some customers are bearing the full cost of the repair while others are being offered "good will" discounts. Appears there had been a service bulliten out for 2 1/2 years on this problem with no sign that MBUSA is stepping up to cover a known fault. roughly 10 updates to the bulliten adding vehichles to the list.

Any other Shop Forum members experiencing this? Not exactly the kind of news one expects when you take your late model Benz in for a CEL... "Oh Mr. Customer, we have to take your engine out and apart.... 5 days and $5K later... good as new"

And... What's to prevent the replacement components from wearing out the same way?... ie...is the problem "really" a faulty crafted part or is it a design issue?"

Finally. what other 06 models have the same 3.5L installed? the R, E, C classes ?

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Jeff
'87 300E
'92 400E
'06 ML350

The first run of production motors had a balance shaft gear that was too soft, and in turn the chain would wear it out prematurely. The new updated balance shaft gear has not shown any isssues.

Please explain what a balance shaft gear is. Never heard such a term before. Are you referring to a vibration dampener?

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Fred Hoelzle

Its the gear that is mounted to the balance shaft. the balance shaft helps smooth out the v6 motor (believe it is a 90* V6, due to the modular construction) by using a counterweight. The gear is driven by the timing chain.

Not just ML's but all MB's equipped with the M272/M273 series engines from 2005-08.

That is 1 of many reasons MB now suggests a maxi mun oil service of 10K miles as well.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

I just had this done to my 2007 GL450, under warranty thank heaven!

It was a shock to visit the dealer and see my *new* GL sitting there with a gaping hole in the engine compartment!

Thankfully, they really took their time and the tech working on it was a senior tech with experience. They had already done a few of these. They replaced a few other items there as well, everything covered, including all the solenoid units. I took a look at the engine afterwards with a critical eye and things looked really good, nothing out of place.

I asked the tech if there were any stray bolts left at the end, he just gave me a look...

Talk about a massive job for a tiny part. He showed me the worn gear, the teeth were visibly worn, substantially so. The engine appeared to be in excellent shape otherwise, everything clean and no signs of wear.

Oh, and they also fixed my wouldn't-stay-shut coin tray.

C.

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Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon

Are the shorter intervals supposed to help prevent wear on this part?

Any more insight on the M273 I should be aware of Doc? TIA.

__________________
Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon

Got the wife's ML back today... so far so good. The rap sheet i 5 pages of R&R this, R&R that, plus a list of every sleeve, seal and bolt you can imagine... Also replaced Oil Bump & pick up tube, balance shaft (of course), chain tensioner, cam plugs, valve timing solenoid units, every fluid that flows through its veins.

QUESTION - what's up with filling the engine with Mineral Oil, running, draining then changing the oil again and replacing the Mineral Oil with typical Synthetic ? just curious what's special about MO?

Finally - what would happen if one did not have this issue resolved?

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Jeff
'87 300E
'92 400E
'06 ML350

Using regular "mineral" oil is FINE...but oil change interval needs to be 5K miles not 10K!

Also in cold weather you might need to run lighter weight oil.


The timing chain can jump & bend all of the valves! Plus you wouldn't pass your emissions test.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Exact same here, it's obviously the same procedure at all dealers. Same parts replaced, etc. They also did the multiple oil changes. I'm guessing that they do the initial quick run and drain to flush out any contaminants that may have entered the engine during the R&R. Hence the use of cheap oil. Since they are only using that oil change as a flush, why use full synthetic? Makes sense to use cheaper oil. Then they verify operation and no codes and then fill up with the proper oil and filter.

On one hand, it's sad to see such a beautiful piece of engineering in pieces! On the other hand, the engine gets an early mid-life inspection and you get all fluids changed (like compressor oil, refrigerant, antifreeze, etc.).

__________________
Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon

Here is what the offending part looks like and comparison pics:

Attached Thumbnails

       

Here is a link to the attached TSB document for your viewing pleasure:
http://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=681441

Thanks Darktech, useful info.

__________________
Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon

Ahh the wonderful M27X balance shaft issue. I haven't had one in awhile so I'm probably due to get one. It's kinda like playing russian roulette when you get a m272/3 engined vehicle with the check engine light on. You have to ask yourself, "Do I feel lucky today?" and hope that the fault code turns out to be for just one of the cam adjuster solenoids and not the the fault codes-o-death, 1200 and 1208, indicating constant adjustment.

Anyways for anyone wondering the vehicles I've seen come through needing this have been mostly 2006-7 models but not limited to that as MBDOC said. ML350, R350, C230, S550, GL450 just to name a few. My experience has been limited to 2 GL450's and one ML350.

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1980 500SE/AMG Euro
1981 500SEL Euro
1982 380SEL
1983 300TD
1983 500SEC/AMG Euro
1984 500SEC
1984 300TD Euro
1986 190E 2.3-16
1986 190E 2.3
1987 300D
1997 C36 AMG
2003 C320T 4matic

past: 1969 280SE 4.5 | 1978 240D | 1978 300D | 1981 300SD | 1981 300SD | 1982 300CD | 1983 300CD | 1983 300SD | 1983 380SEC | 1984 300D | 1984 300D | 1984 300TD | 1984 500SEL | 1984 300SD | 1985 300D | 1986 300E | 1986 560SEL | 1986 560SEL/Carat | 1987 560SEC | 1991 300D 2.5 | 2006 R350

I've got two at my shop right now, an ML and an R Class. It looks like two of my guys will be busy for the next few days. They're both out of warranty, but I'm sure MB will help out.