hx_guy

It's so odd how you can have two of the same car, same model, same year...yet they can be very different.

We had a 2012 E350 Bluetec lease which we turned in another then purchased a 2012 E350 Bluetec. The first one had a very distinct diesel sound, especially at idle...gurg gurg gurg...and even when accelerating it had a certain raspiness to it. It also got good gas mileage, averaged about 30 MPG.

The second car however it different...idle is barely noticeable and acceleration sounds more like a gas engine. Could be my imagination but I also feel it doesn't quite have the torque of the first one, doesn't quite push you back in the seat or strain your neck the same way. As far as mileage, seems to be averaging around 25-26 MPG. Yes, I'm sure it's a diesel, I even double checked.

Could there be something up with it? Should I take it in and have it checked out? It's a Certified Pre-Owned so you'd think everything was checked out and done before it was sold.

ImInPA

Probably in your head. I know over time, the engine cover comes loose on the diesels and creates the sounds you mention. Maybe your "pushing back into the seat" acceleration tests are causing the low mileage? In any event, all things being the same, there should not be that big a difference in the fuel mileage. I am guessing your driving style is different in testing out the new CPO vehicle. For mpg to be that far off, you would see some sort of error I would think. You do not state if they are both the same E350s. Is one Sport and one Luxury, or are they both the same?

hx_guy

Both exactly the same Sport models, though the CPO has the P2 package while the old car didn't, otherwise identical. And the "pushing back into the seat" was something the old car, which got better mileage, exhibited. The new car doesn't feel as torquey, yet gets worse mileage.

DerekACS

What is the difference in odometer readings between the two cars ?

I wonder if one has been previously driven in far different conditions, e.g. short distance urban driving and the other mainly highway miles ?

One engine could have carbon build-up (much rarer in MB diesel than in a BMW diesel) while the other might be much cleaner ?

My car is a 2013 E350BT; it has seat-pressing torque and effortless passing power. Yet, it will easily return 5.7 L/100 km or 41 mpg (US) for highway cruising.

Since your E350BT is still under warranty, I would suggest you have the engine properly tested and assessed for performance standards by a MB dealer.

hx_guy

The old car we had since new and turned it back in at 30,000 miles.

The new CPO car has 21,000 miles and it was a Southern California car (vs Phoenix) so it could be that it was driven differently but would that make a difference really?

I will have the dealer take a look just to make sure.

ImInPA

The difference in the performance would not be accounted for with different driving styles and such minimally different mileage. That the "weaker" one is smoother and quieter says it actually has a better combustion process taking place, as the diesel clatter is actually a result of the combustion process. The only thing that makes any kind of sense is if there is something wrong with the transmission, and, rather than starting in 1st or 2nd gear, you are starting in 5th gear. A possible fuel leak could account for the reduced mileage. There was a recall on the fuel fuel filters for possible leaks aron the O-ring. Other than that, it is likely in your head.

hx_guy

What's funny too is that the new car actually has a buttery smooth transmission whereas the old car had the jerk that a lot of people complain about from 1st to 2nd and sometimes 2nd to 3rd.

Isn't there a way to reset the transmission somehow?

hx_guy

You know, maybe the car just needed a little settling in...learning how we drive? I don't know, but we tried to get better mileage and sure didn't have any problems. Averaged 38.7 MPG (indicated) on a 60 mile round trip 90% highway trip yesterday and then my wife had a 100 mile round trip today and di an indicated 37.3 MPG so I'd say that's pretty good. For the current tank full, it shows an indicated 30.2 average, 523 miles so far and it's almost empty, maybe another 25 miles before it needs to be filled up.