How are the W211 Bluetecs?
 

Just curious if anyone has any thoughts on the Bluetecs. People here seem to really love the CDIs, and I just wonder why I never hear anything about these cars. I realize that they use AdBlue. Are there any major reliability issues with it, or is it just too expensive for the average forum member here :D?

EDIT: I didn't realize that the W211 Bluetec utilizes a DPF, but no AdBlue...

the OM642 is much more complicated and much more needy.

The oil coolers will leak until the new purple Viton seals are installed.

The intake manifolds will need to be replaced due to the plastic flap linkage wearing out from excessive carbon build up.

EGR faults due to excessive carbon build up in piping to the intake.

Timing chains will stretch to the point where you get a nasty chain slap noise at cold start.

The DPF filter will become clogged.

All these issues seen usually before 100k miles or not to far after. This is all personal hands on experience with this engine not hear say.

Yep, the 642 is just more complex, harder to work on, repair intensive, and not as durable. The 648 seems to pack on the miles with very little besides regular maintenance.

Well then.

The mannerisms of the Bluetec are completely unlike a Diesel. Drive one of these, and you are positive it's a gasser V6 under the hood. The 7 speed transmission is so smooth. That engine never feels iike you are revving it up.

Well.... I guess it is a V6, but still...

We have a 2008 E320 Bluetec
 

Bought new. We have had NO repairs on this car. Only by-the-book preventive maintenance by our unusually excellent and honest dealership (McGeorge in Richmond, VA). This is my wife's ride and I am forbidden to do anything to it even though I do all maintenance on my 1983 300CD.

The car is rocket ship fast and a great place to sit but I don't like it as much as I do my 1983. This is definitely not a DIY car. The systems are complex and when the plastic engine cover is removed the underhood looks like a jumble of spare parts thrown into a box. Moly, based on your posts, I don't think you would like it. It doesn't have the W123 soul and maintenance accessibility.

My '08 has 90k. I've had none of these problems. So the problems are not universal. Either that, or I am in for a really rough next 10k miles. ): That said, I am expecting to fix some of this stuff someday. On the plus side, there is no sbc to wear out.

My brother bought an '06 CDI new and is still driving it. It's needed 3 minor repairs in 10 years. Come to think of it, that's the same number of repairs the bluetec has needed so far.

Just curious...what are the alleged advantages of the OM642 over the OM648?

I own a 2008 Bluetec. No exhaust fluid required but a special motor oil is required (A version of Mobil 1 that meets the MB spec.). I bought the car used with 93,000 miles 2-1/2 years ago. It now has a little over 160,000 miles. No engine maintenance except oil and filter changes. Did change the serpentine belt at 100,000 miles --- the old belt looked perfect and it is riding in the trunk, just in case. The local mechanic did a pre-purchase inspection and found oil weeping from the usual oil cooler gasket/o-ring and the dealer lowered the price $1,000 instead of fixing it. Now 67,000 miles later the oil is still weeping but not enough to add oil before the 10,000 mile oil change interval. The oil pools in the plastic belly pan so there is no dripping on the garage floor. There is a lot of labor involved in replacing the cheap part to stop oil leak --- I will not have it replaced unless the rate of leaking increases. I paid $17,000 for the car and I am very happy with it. I would make the same purchase if I had to do it all over again. There have been two repairs to the car since I bought it. One involved a loose electrical connector inside the driver's side B pillar that was causing a faulty "fasten seat belt" message. The other was a problem with the trunk latch which was replaced. The original owner replaced one lower ball joint and there were some sensors replaced very early in the cars life. This car is repaired by the book - no shortcuts. So, all other "repairs" have been recommended preventive maintenance items.

It met tougher environmental standards.

It is shorter than a straight six so it could fit in a variety of chassis. ( I am pretty sure I could fit one into my SLK.)

Powerful, efficient, intimidating to look at to a DIY'er.

It meets newer, tighter emission standards and hence is legal to sell. The om648 was too dirty to be legal under new standards introduced in both the U.S. and Europe in the 2008-ish timeframe.

I have the OM642 in my wife's 2008 ML320

We picked an 08 because it was the last year in that series that does not require DEF

126 k miles...so far the only major hiccup has been glow plugs.

It does need the special oil so a DIY oil change is around $100 or so.

Very intimidating to look at especially compared to an IDI inline engine.

I'm not sure why everyone dislikes the DEF. You fill it up with each oil change 10k miles (in my case probably 2 years) and it's less than 50 bucks...

It's not the DEF per se but the fact that MB deletes the spare tire for the reservoir.

Run flat tires are very expensive, 2x the cost and 1/2 the life of regular tires. Especially 19's as used on the MLs.