PeachParts Mercedes-Benz Forum - View Single Post - Opinions: 2014-2016 W212 w/ OM651

TimFreeh · #6 08-05-2019, 10:50 AM

I have two OM651 engines in service in my family, a 2013 GLK250 and an 2014 E250.

Between the two cars I've now 140K miles in ownership experience. The only engine issues I've had over this time is a split intercooler hose on the GLK about 20K miles ago. The hose from the intercooler to the intake swirl valve assembly developed a leak, tripped a check-engine light for low-boost condition. Car still ran fine but it was way down on power. This happened while I was away from home and was quickly diagnosed and fixed by a local MB dealer.

Emissions systems on these cars are admittedly complex and are going to be pretty expensive for the average DIY'er to handle. In addition SCN requirements make simple replacements of anything in the emission control system chain like NoX sensors a dealer-only (or independent with a Start Diagnosis system) requirement. To date I've had zero issues with any of the emissions system stuff on either of my cars. The design of the DPF portion of the system could be problematic if the car is operated for extended periods of time in low-speed conditions - the DPF needs a good heating cycle during trap Re-gen cycles.

The amount of torque that is produced from 2.1 liters of displacement is just hard to understand. I started my MB diesel habit with an OM615 220D and every time I'm going up a mountain at 80MPH in 7th gear at 1900RPM in either OM651 powered vehicle I just have flashbacks of making similar drives in my 220D at 40MPH screaming in second gear with black smoke pouring out the back watching the lights from my hazard lights reflecting in the tailing smokescreen as gas powered cars whizzed by me going 70MPH and hoping nobody hit me in the slow lane.

We've come a long way in 40 years.

The CDI engines are just an order of magnitude improvement over the older IDI engines. Just bought an E300D turbodiesel for a member of the family from Jaybob a month ago and spent 8 hours behind the wheel on the way home. The example I bought from Jaybob was a well-maintained and very nice W210 but the torque deficit of the OM606 turbo engine was kind of eye opening to me after extended seat time in the OM651.

The 2005-2006 CDI cars are a very good deal at this point in time. In truth you're getting about 80% of the advantages of the W212/OM651 package at 40% of the cost. If I was thinking of upgrading I'd look for a nice W211 CDI diesel.

YMVV.