Date registered: May 2005
Vehicle: '07 GL320CDI
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Quoted: 1 Post(s)
A better question is to simply ask the differences between the OM648 (I6) and the OM642 (V6).
The first difference is that the older engine arrived in 1998 (in Europe) and the newer engine in 2006. That by definition means newer technology.
The V6 is clearly designed with more stringent emissions regs in mind.
The V6 is aluminum, and is therefore lighter.
The V6 is actually 3.0 l and the I6 is actually 3.2 l.
The same displacement V6 is used in models labeled 280 and 320, the difference being state of tune. With previous inline engines, there was a 270 and 320, the difference being the former was an inline 5.
"Bluetec" describes the exhaust system and not the engine. There is no "Bluetec" reference related to any '07-'08 M, GL, R, or Sprinter. Certainly not every European Mercedes with the V6 is labeled "Bluetec."
Not sure about the Sprinter, but all other USA V6 arrive with diesel particulate filter, which means no diesel smell, no soot on exhaust pipe ends, and requirement for low-ash motor oil. The W211s with "Bluetec" badge have additional exhaust system components (and lower horsepower) but not urea injection. Urea injection arrived with 2009 M, GL, and R, which are therefore 50-state legal.
In my experience the V6 is a much more refined engine, i.e. lots quieter and smoother.
In my experience with Mercedes--dating back to early '80s--older is NEVER better. This is a negative (partly cloudy) way to put it of course, and it's better to say that Mercedes is an upfront company that makes truly worthy innovations when it changes its cars.
In your looking at W211, '07-on means you get a "facelift" model, which has between 1000 and 2000 changes compared to previous versions. Because of the different bodies we own, I can't compare fuel economy between the two engines (in reality it's 10mpg highway) but it wouldn't surprise me if the V6 is a little less than the I6 in the same body--penalty for better emissions control, I imagine. I'd still expect, however, when it's all added up, the newer the better.
Last edited by lkchris; 03-02-2009 at 01:34 PM.