Hello,

I have am new to this forum and the frustrations of dealing with Mercedes. I am the second owner of a 2011 GL350 Blue Tec. It was bought from the original owner in 2016 with all of the maintenance records. Since owning the car it has followed a proper maintenance schedule and had other various repairs done as needed to the car.

About a year and half ago I noticed what I would call "chugging" of the engine while driving in low RPMs. I brought it in to the dealership and was told that it was due to "dirty diesel" and was recommended an additive that went into the tank every 3-4 fill ups. But was told really nothing was wrong with the car and to be on my way.

About two months ago it was still doing this "chugging" and it seemed to keep getting worse. Took it to the dealership who ran all the computer tests etc and nothing came back as a problem. But the chugging was still there. Then they did a compression test and found out that basically the car had lost all compression (sorry not a car person so perhaps I'm explaining this wrong, but it's what I understand to be the problem). I was told the car was essentially a ticking time bomb and at some point would just lose all power and there was no way to tell. And ultimately the only solution is a new engine. This car has only been driven 170,000KM - which is about 106,000 miles.

Sure enough a few days later on a road trip the car lost all power. It can drive on flat roads, but has no ability to make it up a hill or anything, so essentially useless.

I am of the mind that a car that is only 8 years old that has been maintained properly shouldn't have it's engine totally crap out at 170,000KM and that there is some liability on behalf of Mercedes Canada as it seems to be a known issue with this engine that there are problems. I believe it's the OM642 engine. I've been told the repair will be about $30,000 to get a new engine and install it which is just outrageous.

I am curious if anyone has had any luck dealing with the head offices of MB and getting somewhere with making a claim for implied warranty for an engine that is less than 10 years old. So far I am getting the run around from MB and they just take no interest in the situation other than to say it's nothing to do with them, the car is outside of the warranty period etc.

Any insight would be appreciated. Do I take it to another dealer to diagnose the problem? Get the engine rebuilt somewhere else? Fight MB?

Im very sorry you have this kind of issues.
Im afraid you will get 0 help from MB. Technically the car passed warranty period two times. Powertrain warranty is 50K miles.
But you can try. I feel your pain, Im like you, and a lot of other bought MB diesel to last forever and later realize its a ticking bomb.

I have a few questions for you:
How does the car starts when its cold and hot?
Did you lose power at ones or slowly losing ?
Any smog coming out? If yes, what color?

I would take it to an indy shop with good reputation.

The car starts totally fine - I've never had an issue with it starting up at all.
Power was lost while on a highway and passing another car - so it was sort of all at once.
And no smog coming out of the car at all. You wouldn't know there was anything wrong with the car unless you tried to drive up a hill.

So, wow.

More questions. Is your check engine light on?

Do you have any documents from the dealer you can upload? They should have put everything in writing. in fact, its required for the bureau of automotive repair.

Ok, car can't lose compression all at once its a slow process, as far as I know.

Also, you have mention you have all done per schedule, but I would check with indy shop fuel and air filters.

The check engine light as NEVER come on... It is so strange. Attached are documents from most recent check up where they told me I needed a new engine.

Looks like there are more issues with this engine. Oil allover. Yes it can be oil cooler, if engine lost a lot of oil valves and rings might get damaged, and turbo too.
Is there any oil below turbo air intake seal? If yes, it could be turbo actuator has died.
When was the last visit to a dealer before this one?

it visited the dealer in July or 2018 with the same chugging issue. Was told it was dirty diesel and not a problem. But did know about oil leak and was on deck to be fixed but was told it wasn’t urgent or causing issues.

Ditto on that. I've been opening MB diesel engines close to 300k miles and they still had factory honing (grinding) marks on cylinders.
There is no way the engine wear out at this mileage and since the engine starts and runs on idle fine - it has to have some compression.
I would start with asking dealer for compression test results and go for 2nd opinion.

Thank you for all the info. The compression test results are in the PDF I attached a few links above.

When you lose power does the car slow down or does it maintain speed and is just slow to accelerate when floored? If the latter you could have a turbo pipe not fully engaged. I had the same issue and the dealer found the turbo pipe loose causing no boost from the turbo.

The pdf charts are hard to read, but they indicated low compression,, especially on cylinder 1 &2,
That with experienced mechanic should be followed by adding some oil into cylinders, what would tell if that is wear out pistons, or valves.,
Get 2nd opinion.
What are the records for the car? Who was changing oil and what kind?

If I am driving on flat I would say it’s slow to accelerate. But if driving up a hill with pedal to the floor it loses all speed and I feel like the car won’t make it up. For example can be driving 60km/hour, start on small hill and by top barely going 20km/hour - and hill is only 300m or so long, but relatively steep.

Would a turbo pipe issue also lead to no compression? Or not enough compression?

thank you everyone for all the comments!

Turbo issue leads to not enough compression. Not necessarily no compression.

Tell us more about the maintenance records of the car please.

Who did the regular scheduled maintenance like engine oil & filter change, air filter change etc?
What kind of oil & filter?
How many miles or kilometers in-between changes?
Have you checked the oil level in-between changes?
Have you had to add oil in-between changes?

No codes = misfire unlikely.

Oil leak could have fried the swirl motor which will trigger limp mode WITHOUT throwing a code. I would put in the 4.7k ohm resistor and unplug the motor and see. Also, it's worth going under the hood and pulling fuses 100-110 and see if any are blown.

Compression is low but there isnt an indication if its pistons or valve related. Based on the stuff I have seen, it could be the bottom end if it's only done the regular service intervals.

I would NOT TRUST that compression test. The gauge used was a motometer that has paper inserts, those units are decades old and likely never calibrated by anyone since buying it.. I have used them in the past at dealerships and found them to not very accurate, sure the difference between cylinders means something but worry that the overall result is not enough to support a 30k engine replacement. There is something else going on here causing no power and limp mode and the dealer does not have the experience needed for diesels.
It could be all sludged up inside from lack of proper servicing (changing the oil at 15k intervals is long for Canadian winters, especially if driven short distances) and perhaps the oil changes were never done well (cold oil not drained fully). Get it out of that dealership and find an indy place that KNOWS diesels, look for a collection of Sprinters around the parking lot. Every city has a place that delivery guys use and businesses find after they give up on the dealership. Have them check it out, worst case some oil cooler seals and such fixing the leaks on the top end and the flap motor on intake that hates oil (which will run a couple grand total). but better then loosing it. There are products out there to flush the oil system oil also that can help if it is neglected inside and dirty.

I would be very suspecious of the cyl 1 & 2 copper injector seals. That would cause your issue and fool the compression tests.

Diesels run on compression. No compression, no worky at all.
Take it to a different shop.
Better yet, go fetch yourself a decent compression tester from your local auto parts store and test it yourself. You'll at least rule out compression issues (worn rings, valve seals, etc) as the cause of the problems.

Plug in a decent tester to the OBDII port (icarsoft?) and start monitoring what the car is doing and when. Pay attention to your turbo boost pressures as you demand power.

Your local flaps, will NOT have an adapter to the glow plug threads to test compression. And you risk breaking a glow plug in the process if you arent extremely careful.