Concerns over the OM651 engine in ML250/GLE 300d
Thread Starter
Junior Member
Joined: Jul 2013
Posts: 17
Likes: 0
ml350
Concerns over the OM651 engine in ML250/GLE 300d
Hi All,
I have a 2014 ML350 BT and looking to get the 2016 GLE 300d. I really like all the technology it is now coming with. I had a test drive this past weekend of a 2015 ML250 BT to compare the differences between the 6 cylinder vs the 4 cylinder diesel engines. I have to think the 2015 ML250 would be the closest thing to the MY16 300d that is coming. My research between the engine/transmission appears to be a same for the most part. I do not see that the 2016 OM651 bringing any thing different to the table from the 2015 ML250.
Back to the test drive, I felt very disappointed in its performance. The acceleration from dead stop was somewhat lagging. Even at 40mph and hitting the accelerator there was hasitation. It definitely had me guessing if I really want to move to this MY16 GLE BlueTec. I also noticed that you could feel the vibration a little more in the seat due to the missing 2 cylinders.
But the biggest ( and it is PETTY on my part) is I pull through a drive thru and when I roll down my window I just hear the solid diesel ckack-clack-clack-clack of the 6 cylinders echoing off the walls. The sound of “it means business”. But you do that in the ML250 it sounds not as impressive and somewhat cheesy.
The other thing I have done is research both OM642 and the OM651. There is a lot of concern about the OM651 (in the ML250 and coming in the GLE 300d) about the injectors and the timing chain. Most of the review and issues are dated but some are very recent as of last year. If I Google the same for the OM642 no such issues and for that matter not a lot of issues al together.
I would like to hear other experience with the ML250 BT.
I have a 2014 ML350 BT and looking to get the 2016 GLE 300d. I really like all the technology it is now coming with. I had a test drive this past weekend of a 2015 ML250 BT to compare the differences between the 6 cylinder vs the 4 cylinder diesel engines. I have to think the 2015 ML250 would be the closest thing to the MY16 300d that is coming. My research between the engine/transmission appears to be a same for the most part. I do not see that the 2016 OM651 bringing any thing different to the table from the 2015 ML250.
Back to the test drive, I felt very disappointed in its performance. The acceleration from dead stop was somewhat lagging. Even at 40mph and hitting the accelerator there was hasitation. It definitely had me guessing if I really want to move to this MY16 GLE BlueTec. I also noticed that you could feel the vibration a little more in the seat due to the missing 2 cylinders.
But the biggest ( and it is PETTY on my part) is I pull through a drive thru and when I roll down my window I just hear the solid diesel ckack-clack-clack-clack of the 6 cylinders echoing off the walls. The sound of “it means business”. But you do that in the ML250 it sounds not as impressive and somewhat cheesy.
The other thing I have done is research both OM642 and the OM651. There is a lot of concern about the OM651 (in the ML250 and coming in the GLE 300d) about the injectors and the timing chain. Most of the review and issues are dated but some are very recent as of last year. If I Google the same for the OM642 no such issues and for that matter not a lot of issues al together.
I would like to hear other experience with the ML250 BT.
Senior Member
Joined: Sep 2012
Posts: 323
Likes: 31
From: Ottawa ON Canada
2015 ML350 Bluetec
My own opinion when I test drove a ML250BT in Florida last Feb... didn't even drive it off the lot!!! The 250 was down on power, and noisey! I had a GLK350, was looking at options to change up to.
The ML 400 was decent, lots of grunt, & quiet! Fuel economy was worse then my GLK! I was surprised at the power/smooth running engine and quietness of the 2015 ML350Bluetec when I returned to Canada. Thank goodness MBCanada kept the ML350 for 2015! The 4 cylinder engines just sound rough, and their performance is minimal (MY OPINION). The new Volvo XC90 was in the running, but again, 4 cylinder, even with supercharging and turbo, performance was subpar and engine was noisey throughout the RPM range!
The ML 400 was decent, lots of grunt, & quiet! Fuel economy was worse then my GLK! I was surprised at the power/smooth running engine and quietness of the 2015 ML350Bluetec when I returned to Canada. Thank goodness MBCanada kept the ML350 for 2015! The 4 cylinder engines just sound rough, and their performance is minimal (MY OPINION). The new Volvo XC90 was in the running, but again, 4 cylinder, even with supercharging and turbo, performance was subpar and engine was noisey throughout the RPM range!
Senior Member
Joined: May 2008
Posts: 477
Likes: 30
From: Maricopa, AZ
2012 S63, 2013 E350 Bluetec
I have a '13 ML350BT that is coming off lease in about 10 months. I'm over on miles and was planning on shelling out some bucks for that, but I really like this vehicle, have had virtually no problems with it and am not thrilled about the idea of getting a 4 cylinder diesel in such a heavy vehicle. I made a decision a couple weeks ago to just go ahead and buy this one at the end of the lease. I purchased a third party warranty just in case things go south.
Senior Member
Joined: May 2013
Posts: 377
Likes: 40
From: Chicago, IL
2023 EQS 580 SUV
When we were looking for a diesel sedan we didn't even bother test driving the E250 and bought a 2014 Audi A6 TDI. I love my 2014 350ML Bluetec and I hope that Mercedes will offer another V6 diesel here in the US by the time I'm due for a new SUV. I haven't tested the ML250 and I'm not interested either, I might just go for the BMW X5 diesel instead.
Senior Member
Joined: Mar 2015
Posts: 442
Likes: 29
From: Ohio/Florida
'10 C300, '15 ML250BT, '22 M850i Vert
I just turned 3000 miles on my 250 and couldn't be happier. MPG is fantastic and the power is way better then I expected. The engine is very quiet and it has better throttle response then the 350BT I drove prior to buying. I'm sure the twin turbos contribute to that. I paid $6k more for a new '15 then I could have got a used '13 with 24,000 miles for. I also wish they still imported the 350BT but if you buy the 250 you won't be sorry.
Super Member
Joined: Dec 2010
Posts: 831
Likes: 13
From: N.C. USA
2015, ML250 BlueTEC
Just turned over 5,000 mi. on my loaded 2015 ML250. Home after 2,000 mi trip. That was the real test. Great car. Unless you are a speed demon it has all the power needed. On mountain Interstates a minimum of down shifting. No problem passing. Unless I told any riders it was a diesel they would never know it. Quiet and very smooth. In fact I have a C300 loaner now & the gas 4 cyl is not as smooth as my 250BT. Overall mileage for the trip was 33mpg. My cruise was set in the low 70's. A 300 mi part thru KY,TN & NC mountains averaged 35.6 mpg. Have DISTRONIC PLUS which may have helped.
I did not buy my 250 for any economy reasons. It just happened to be @ my local dealer when I was ready to buy. Replaced 18" wheels w/19". Have also installed lowering springs. Looks great & also a large improvement in handling. It won't burn rubber but is a comfortable ride. With these mods find that I am going faster without realizing it.NO rattles,squeaks,wind noise or leaks. Have had MANY MB's over the last 40+ yrs & this is one of the best!.There are benefits to buying the last year of a model.
I did not buy my 250 for any economy reasons. It just happened to be @ my local dealer when I was ready to buy. Replaced 18" wheels w/19". Have also installed lowering springs. Looks great & also a large improvement in handling. It won't burn rubber but is a comfortable ride. With these mods find that I am going faster without realizing it.NO rattles,squeaks,wind noise or leaks. Have had MANY MB's over the last 40+ yrs & this is one of the best!.There are benefits to buying the last year of a model.
Last edited by greasykid; Jun 26, 2015 at 11:18 AM.
Newbie
Joined: Dec 2013
Posts: 11
Likes: 1
From: Reno/ Lake Tahoe Nevada
2013 ML350
ML250 BT is great
I was one of those who had a 2013 ML 350BT with major engine problems. After 18 months MB agreed to replace it with a 2015 ML 250 BT. We now have 25,000 miles on this vehicle and love it. In fact today I ordered a GLE 300d to replace my BMW X 5 which is 13 years old. I have nothing but good words about the 250. We live near Lake Tahoe and it has excellent performance for mountain roads. We drive to Palm Springs about five times a year and it is a great road car. We tow a 5000 lb Jeep Wrangler twice a year and it has plenty of power and performance in all terrain. No diesel will snap your neck back when you step on it, but passing it accelerates quickly for safe travel. I especially like the 33 mpg we get on the road.. I can hardly wait till the GLE arrives in August.
Last edited by Skiwithry; May 4, 2016 at 07:01 PM.
