M272 Balance Shaft Issues – E350

I went to look at an 2006 E350 W211 Estate today and had learned on the Topklasse forum that the M272 engine manufactured from 2005-2007 suffers from a potential defect.    From what I understand as this engine is a 90 degree V6, there were additional components required to make it run smoothly and these and the timing gear can suffer from premature wear.     More information can be found here.   The part is called the Balance Shaft.  The ideal angle for a V6 is 60 degrees.   The M272 is 90 degrees so it can be built alongside a V8.  90 degrees is the ideal angle for a V8.

This was enough to put me off buying a car I would have otherwise bought.   Most likely I’ll be looking for an ’04 or ’08 model instead. Late 2007 models are also generally fine.  Its a shame as it was a nice car.  From what I read, repairing the M272 balance shaft means a partial disassembly of the engine and at least $7,000.  The dealer was also unwilling to let me have a mechanic check to see if the job had been done.   That was a showstopper for me.

The link to the Topklasse forum above also contains the factory documentation to look up the engine numbers of affected cars with this M272 balance shaft problem.  It also outlines the scope of the work required if such a car is to be repaired.  The early build M273 V8 engines also have problems, although not as severe as the V6.  There was a class action lawsuit in the USA that provided relief to those owners.

Update 2017: I later purchased a 2007 model E350 Wagon that falls outside the affected engine numbers.   The Wagons can be hard to find as they were more expensive than the equivalent SUV.   They are a much better car though.

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