Is it an OM642 ?

[Robbi57]

Hello fellow enthusiasts

This is my first post, and although I’ve had a CLK for a couple of years, I am considering purchasing an E350 CDI BlueEFF Sport Tip Auto 2010, which has a 3.0-litre V6 engine.



However while there are issues with any engine and history is crucial, I read this article from across the pond that alarmed me titled

“Here's Why You Probably

Shouldn't Buy A Mercedes-Benz With The OM642

V6 Diesel” on the theautopian.com website, authored by Thomas Hundal, posted October 26, 2023.



I am test driving the above mentioned vehicle tomorrow and I wondered whether it has under its bonnet the OM642 engine; and if so should I take Mr Hundal’s advice?



Thank you for reading this and apologies if I am have overlooked the obvious!

Kind regards

Rob

 

[ALFAitalia]

That's exactly my car...down to the year. ... and yes it has an OM642. Not owned it long... but so far so good. Very smooth (probably the smoothest derv ive driven), near AMG levels of torque, fairly economical with a nice exhaust sound if pressing on. I had to replace the turbo after a poorly fitted (cuz its a sh1te design!) orange turbo seal was partially sucked onto it....but I fitted a recon turbo myself so the bill was only around £400. I'm slowly working through a few very minor oil leaks. I love it.

 

[Jukie]

I have a 2011 E350 CDi. Had it over ten years now. It’s over 126k on the clock. I have the revised 265hp engine. It’s a peach. Never had a problem with it in my ownership. Couldn’t recommend it more.

I concur with Alfa about how smooth yet punchy it is.

 

[toteimerced]

Love mine, loads of torque, good power, smooth, quiet for a diesel, no worse than any modern derv engine for reliability, much better than BMW, with there snapping timing chains.

 

[DSM10000]

Yes it is the OM642 engine. There have been several iterations of this during it's production.

I have no idea who this person is or why you or anyone should pay any particular attention to their views.

The engine can have faults, oil cooler seals being one but they were redesigned during production.

Show me any modern engine, regardless of the manufacturer that doesn't have some problems. I ran an OM642 to over 180,000 miles and apart from routine servicing it only required a replacement EGR and Turbo actuator plus an exhaust back pressure sensor.

 

[Larkone]

Same experience here. 171000 miles now, oil cooler seals done done at 150K, refurb turbo actuator and PCV at £130K. Otherwise just oil changes and filters.

 

[Robbi57]

That's exactly my car...down to the year. ... and yes it has an OM642. Not owned it long... but so far so good. Very smooth (probably the smoothest derv ive driven), near AMG levels of torque, fairly economical with a nice exhaust sound if pressing on. I had to replace the turbo after a poorly fitted (cuz its a sh1te design!) orange turbo seal was partially sucked onto it....but I fitted a recon turbo myself so the bill was only around £400. I'm slowly working through a few very minor oil leaks. I love it.

Thanks ALFAitalia. Ouch! A badly designed and poorly fitted turbo £400, and that’s I assume you doing the labour. Thanks so much for the info.
Best wishes
Rob

 

[ALFAitalia]

Yes....me fitting it...that price included turbo with all required gaskets, oil & filter, as you should change that after a turbo failure, gaskets for turbo and turbo pillar. It cost more at first but I got £100 back on returning my old turbo for reconditioning.
The turbo is neither badly designed or poorly fitted from the factory but the orange gasket and the way its clamped between the inlet manifold and the turbo is indeed a rubbish design. The turbos for them are relatively cheap as reconned units as so many Merc vans etc use the same unit.

 

[st13phil]

I wondered whether it has under its bonnet the OM642 engine; and if so should I take Mr Hundal’s advice?

Yes, and No. In that order.

As others have already mentioned, the OM642 is used widely across a variety of models and has a strong (and well-deserved) reputation for refinement, excellent drivability and reliability.

 

[BTB 500]

I am test driving the above mentioned vehicle tomorrow and I wondered whether it has under its bonnet the OM642 engine; and if so should I take Mr Hundal’s advice?

I've run an OM642 from new for almost 18 years and about 180k miles. My version is in a mild state of tune (204 bhp), and is EU4 with a DPF.

It's had glowplugs fail steadily from about 30k miles onwards. The control module (relay) and special 'mega fuse' have also failed. A bunch of sensors have failed including fuel pressure, crankshaft position, DPF pressure, DPF temperature, and mass airflow. The EGR valve went too. Many of these are considered 'normal' faults on modern(ish) diesels. Perhaps I've been unlucky to have so many of them happen on mine though.

More seriously (but *much* less common) the exhaust manifolds have a steel liner which can delaminate, dropping metal fragments into the turbo. That happened on mine - engine out job to replace the manifolds and turbo, which took 2 weeks at a dealer and cost nearly £4k (after a goodwill contribution from MB as it was 1 owner with FMBSH, and this is a known issue). This was on my Vito but it can happen to other models with the OM642 as well, although it is pretty rare.

The glowplugs are a minor irritation but everything else put the vehicle off the road (either not running at all or in limp mode). Apart from the glowplug controller and fuse all of the above issues occurred between roughly 85k and 95k miles, so if I'd sold the vehicle before that or bought it after I would probably have considered the engine to be pretty reliable. As mentioned the OM642 was fitted to a huge range of MB vehicles from C Class to S Class, their SUVs, Vito and Sprinter vans, etc. Generally it's well regarded.

 

[DSM10000]

Thanks ALFAitalia. Ouch! A badly designed and poorly fitted turbo £400, and that’s I assume you doing the labour. Thanks so much for the info.
Best wishes
Rob

A new Turbocharger from Mercedes is around £2000.

A properly reconditioned unit is no problem. Turbochargers are wear and tear items.

 

[ALFAitalia]

I was annoying that it was destroyed by a small piece of rubber!!! My old car, the turbo was on it original with 175,000 miles.

 

[BTB 500]

I was annoying that it was destroyed by a small piece of rubber!!! My old car, the turbo was on it original with 175,000 miles.

The Audi 1.9 TDi we had was on similar mileage when we sold it and we'd never had to touch the engine apart from a (precautionary) cambelt change. Even the glowplugs were original AFAIK.

Unfortunately later diesels have a lot more 'stuff' to go wrong, even without AdBlue

 

[toteimerced]

The orange intake seal should be part of the service imho, cheap as chips on eBay and easy to change, prevention rather than cure, just make sure you get the correct one, as there are several types.

 

[philnewmerc]

I have the 265 bhp version in a C class: Really smooth for a diesel especially once driving, its almost silent; very punchy overtaking with torque not far off AMG levels; no issues on mine but its only done ~100k; mpg is either good or poor depending on your perspective, ie, it's a very quick Q car with a 3 l turbo V6 engine that does an incredible 36 MPG*** when driven sensibly; or, it's a diesel that only does a paltry 36 MPG ! I test drove a 4-cylinder 250 diesel and I was surprised how noisy it was in the cabin, but with hindsight I think I would have preferred the fuel saving... Basically I would say if you do 10k miles per year, and they are longer trips, then it's perfect. But if you are more towards 20k a year, and/or shorter trips sub 20 miles, the 4 cylinder would make more sense as I found that the V6 takes a lot of warming up before it becomes economical. On long motorway or A road trips it will do 42 MPG no problem, which I think is fantastic, but anything sub 20 miles is about 25-30 mpg, which is a bit rubbish for a diesel and brings the overall average down. My running average so far over 6,000 mi is 36 MPG.

***NB: My MPG figures are calculated at the pump, not taken from the dashboard. If you believe the dashboard then my car does an average of 42 MPG: that's the figure a lot of owners will tell you!

 

[ALFAitalia]

As ive said before....my dash is always within 1 to 1.5 mpg of spot on. Warms up really fast too... much faster than my old 4 pot ALFA.

 

[johnsco]

I bought the W211 E280cdi Sports Estate in January 2015, with 111,000 miles on the clock.
Since then, I've taken jt to 203,000 miles.
It's been a great car - My work-horse when I was working and my daily driver ever since.
The OM642 has had a reconditioned turbo from Essex turbos.
It's had a set of glow plugs very recently.
I've done all my own routine servicing, although the replacement turbo was done under warranty shortly after I bought the car.
It eats the miles and will return 42mpg on a long run.
It runs as sweetly now as it did the day I bought it.
A real work-horse and a great car.

 

[toteimerced]

If mpg bothers you, if you can stretch to it, the later facelift models are better on fuel, especially the nine speed transmission version, that arrived in 2014, but beware, they come with the troublesome AdBlue system, unless it’s been deleted of course.

 

[ALFAitalia]

No way an Adblue Merc will ever be on my drive.......I was going to say an Adblue car , but it only seems to be Merc that can't make an Adblue system fit for purpose.

 

[BTB 500]

it only seems to be Merc that can't make an Adblue system fit for purpose.

Sadly not, they all seem to have similar problems.

We need to replace the Vito really ... decent vans are crazy expensive nowadays, and there aren't any that look like a sensible long-term ownership proposition any more.

VW/Ford have a 2.5 litre petrol hybrid that avoids AdBlue but obviously has the complexity (and weight) of a hybrid system. Hard to know which would be better after 5-10 years!