[QUOTE=jcyuhn;3286344]I am not a fan of the OM642 V6 diesel used in the ML (and many other Mercedes models). The reason being it has two common and expensive repairs. The first is a leaking oil cooler, located deep within the "V" of the engine. The typical repair cost is $2500. The second is the intake port shutoff motor. The OM642 has throttle flaps in the intake manifold. They are used to create manifold vacuum to increase EGR flow. EGR is used to control NOX formation in these pre-Adblue vehicles. The motor frequently fails, typical repair costs are $1500. You can google up discussions on these repairs and make your own decision on how frequently or rarely they occur.

Have to agree here; Wife has an 08 320 CDI. Love the looks , love the ride; Love the power and smoothness of the om642. Hate the future potential costs of ownership.
Started with oil in the garage; removed the lower panels and lived with cardboard oil stains on garage floor. Oil was coming from oil cooler seal
Then an oil leak developed at the turbo inlet seal and trashed out the swirl motor. Spent a weekend taking the top end of the motor down to the vee to replace seals on the oil cooler; Could not believe the amount of crud in the intake and related plumbing. Cost at dealer for oil cooler seals and swirl motor would have been $3,000 minimum; but they likely would have changed the intake manifold instead of cleaning. So might even up it the cost of the intake.

Oil: MB229.51; gotta use it; go with pentosin; I've heard that there is less buildup of crud over time compared to mobil 1 esp; not sure why.

It's got 120k on it now. If mercedes could somehow get the smoothness of the 642 and the longevity of the 617; they'd truly have something.

I am a diesel guy; but knowing what I now know about the the 642; I would have replaced the wifes ML430 (165k) with an ML350 gasser; no doubt about it.