Flyingman

Folks, new to the MB Bluetec world and was curious if Carbon Build Up (CBU) is common with these engines. I have a BMW Diesel with some 74k on it and so far so good but many have complained about emission codes, injectors, and eventually loss of power and MPG to the point the vehicle goes into limp mode. Service changes a few components but codes never go away and eventually the owner is advised that their intake manifolds and head must be removed and cleaned due to excessive Carbon Build Up.

Some have paid $1,000s, other were covered by warranty.

BMW recently came out with a SIB to Walnut Shell Blast the intakes in place like they already have been doing for years on the gassers. Seems the diesel intakes are more complex than the gassers.

Just curious if this is something that is common in the MB Bluetecs?

Plutoe

I'm gonna invest in walnut futures!!

DubVBenz

I've owned a 2007 E320 Bluetec for a little over four years and put 60K miles on it (purchased with 27K miles). Of all the problems I've had, none of them have been due to carbon buildup. The only engine related problem I've had so far was the ductwork for the turbo air return splitting at high temperatures. The replacement part was cheap.

In terms of other issues:

7G tronic Valve Body replacement due to failing speed sensors (fixed on later revisions, probably 2010+)
Lower Ball joints (all W211s)
keyless entry door handles failing (all W211s)
creaking panoramic roof (all W211s)
Auto trunk closer sensor bad (added some weights behind the license plate, everything works now)

I had been planning on buying and tuning a 335D, but I'm a member of their forums and have read that it's not a matter of if, but a matter of when (around 60K miles) that the head has to be pulled and walnut blasted. And then you have to repeat that process every 60K at at a very expensive rate.

I'm hoping they sorted that out in the 535D, because I'd like to pick one of those up in a few years.

pinebaron

I've owned a 2007 Bluetec from new and have experienced non of the problems mentioned above having done 40k+ miles now. My car was a special order and was one of last few built that year; perhaps I've been lucky.

houseofdiesel

ALL modern diesels have carbon build up problems. ANY diesel with an EGR and crankcase ventilation system will have issues at some point in its life. These are known facts...whether or not you experience a problem is up how the vehicle is driven, what fuel you use and what part of world you are in (Europe's diesel is far better then North America for example). Use of fuel conditioners can help, long drive times help vs short city runs. For Mercedes in particular it is not something the dealer usually has to worry about, the problems arise after the warranty period. Common problems are blocked/gummed up EGR valves, seized glow plugs from carbon going up the bores, seized fuel injectors in the bores, intake swirl motor seizing up.
These problems show up a little later in life on the Mercedes engines, research some Sprinter forums to understand a bit more as they rack up the miles much faster and more hands on in nature, but yes carbon build up is a problem for long term reliability/servicing.