cyber3d

How many of you are above 50K miles (80K kilometers)?

Have you had catastrophic engine failure?

dalazernet

Not terribly useful without model year of vehicle since the engine changed at 2020. FYI

karmikan

Where are the people who have reported engine failures? Not too informative without their input.

crconsulting

Well, this person seemed to get to 230,000 miles OK
230k GLC
And this person to 160,403
160,000 mIle GLC
and there’s at least four other GLC’s in the 159-160k mile range with clean carfax’s
159k GLC

Autotrader is littered with 200k mile cars that use that power plant….

Now I do not want downplay the frustration of any owner that this happened to but,
statistically, it’s very difficult to gauge true failure rates from an Internet forum.

Most people get on to these forums if they have issues, the people who happily drive 200k without incidents never post 😀

Just to expand further on this: these are JUST the US - GLC sales numbers from ‘16 to ‘19:
2019- 73,655
2018- 69,729
2017- 48,643
2016- 47,788

Say of all those cars in the US you lose 10-20 engines.
What is the failure rate? Less than .01%?

It’s statistically IMPOSSIBLE to have 0% engine, transmission or drivetrain related failures with those kind of production numbers. It would be nice, but no MFG’er can claim this.
Remember those are ONLY US sales above….

apsmbw

Mine- just replaced engine on my 2019 GLC 350e. I will add that my dealership/ Mercedes treated me very well over the whole ordeal. She’s back in business! Picked up Friday- fingers crossed.

karmikan

I'm guessing that your estimated failure rate is understated by an order of magnitude. There are at least 2 threads on this site with at least 10 reports of failures. It's true that there's a tendency for subscribers to report problems rather than non-issues but an overwhelming percentage of owners with problems are not aware of these sites and therefore go under the radar.
We can debate the scope and the statistical aspects of the problem but the effect is undeniable, it's catastrophic. An owner's relatively new vehicle is turned into a boat anchor in an instant with no warning and no recourse. Put into perspective, a 120+ yr old company with a "high-end" reputation is/was producing engines with a fundamental but apparently systemic mechanical problem and absolving themselves of any responsibility. This is inexcusable.
Right now I feel like my homeowners insurance has been cancelled, the fire brigade has gone on strike and someone is running around with a flamethrower. It doesn't help that statistically there is a 0.25% chance of my house catching fire.

crconsulting

I'm not here to pour salt on your wounds or somehow defend the corporate empire of Mercedes. I'd be pissed too. I think it's important to clarify why I'm posting here, as I said above, I'm not here to downplay your failure (or anyone else). I've had pretty extensive experience within the automotive service and manufacturing industries and failure analysis experience that comes with that. I also have a vested interest in finding a true cause as I do have a GLC in my stable. My point with the failure rate is, it's probably not on their corporate radar. Whether that is on purpose or not, is also debatable. We know that is standard operating procedure for most companies across all industries these days. Also, that there is a lot "lost in translation" between dealerships tech/service writer and top tier corporate leadership. Same as any other large corporate entity.

Of course none of this is any consolation for you or anyone else with a $50k boat anchor....

Agreed, but for some perspective .01% is a failure rate typically associated with the aerospace industry, where catastrophic failures cost lives. Automotive failure rates are higher. Even the much lauded as "Reliable" Toyota/Lexus is not immune: Toyota Engine Recall

As another example, Total Europen sales numbers dwarf sales in the US. (of course some use a different power plant)

2019: 109,095
2018: 125,143
2017: 111,193
2016: 70,349
2015: 17,708

When looking at these numbers, we have to ask, why aren't we getting more widespread reports of failures in Europe?
We need to try to understand why this is happening. Even if you, or anyone else were to sue Mercedes, It would be important to PROVE why this is happening for any chance of success. I believe without fuel analysis, it would leave any case wide open for legal rebuttal.

Ring land failures are typically associated with preignition/detonation issues. I suspect some of this may be fuel related, either as a catalyst or primary cause. If you're interested you can read some of the links for a quick primer:
See my Post #82 here

I noticed you're in Canada, so can not speak of fuel quality there, but in the US, fuel quality can vary greatly....
Not to mention possible fuel switching by unscrupulous station owners or even honest mistakes.

Typically design and materials issues tend to show up in large numbers consistently, across the models affected, no matter their geographical location. Tooling/tolerance irregularities can be more sporadic, but still I would think we would be seeing more worldwide failures. Also Cylinder #1 appears to be a common first failure point. Lean condition exasperating preignition/detonation?
We're seeing many of these engines last over 200k miles and yet some grenade with less than 50k miles. Not very consistent....

Fuel is a wildcard. It's one of the very few variables that would affect North American cars and not European models. That's not to say that bad or low octane fuel failures aren't possible in Europe, but one would think we should be seeing larger failure rates over there from manufacturing issues. Even the UK forums seem to have less chatter about these engines.

Agreed, we're after the definitive cause part in "cause and effects"
Also, just as an important question is: what part, if any, the knock sensors and tuning are playing here? Looking at this, with these production numbers, and clusters of failures, fuel appears to be a suspect that should be looked at & tested in the event of a failure.

None of this is going to bring any relief to those who already have suffered failures, but trying to find a definitive answer may help those who haven't been affected yet.

karmikan

Thanks for your thoughtful post, although you imply that I'm one of the unfortunates whose engine has cratered. Thankfully I'm not -yet.

Exactly! This is where MB could step up and use their considerable resources to help their customers. Is the problem fuel octane variability? Would octane boosters help? Is the knock sensor threshold set too high? From the admittedly small sample of failures it seems that they occur on the #1 cyl, is this meaningful?. Like many corporations, it would seem that their first priority is to protect their corporate image above all else. Too bad.

Not sure that I agree that Europe is largely free from this issue. A while ago I started to explore avenues that would make it practical to hang on to my car for the long term. I came across this dealer:
.
https://premiumtuning.hu/categories/...rods-1127.html

Here's what I posted on another thread on this site. "Looking around for options I came across forged piston kits made by Wossner, the kit includes the wrist pins. I contacted one of their major distributors who is in Hungary and they confirmed that the M274 pistons do seem to be a problem, so much so that they are currently sold out. I've asked them to contact me when more kits come in." Nothing so far.

Packin4

Here is something relatively new to be aware of that particularly affects small, turbocharged, direct injection 4-cylinder engines: LSPI, or Low Speed Pre-Ignition, which has been causing engine failures due to the engine oil specification (or lack thereof). I know MBZ says 229.51 is specified for my 2020 GLC but it does not meet the "new" specs to prevent LSPI. I found the link below to be very informative. Luckily, more oils are coming to market to address the LSPI issue. YMMV and good luck.

https://www.hagerty.com/media/mainte...wsletter_NewDD

lastrycjusz

Also not useful without engine type. OM651 is completely different than, let's say, M276.

karmikan

Thanks for this. It's the first I've heard of LSPI and the linked article addresses some unanswered questions. Some of the posts from people who have experienced engine failure mentioned that their driving style was not aggressive. You would normally expect pre-ignition to be associated with high load/high rev scenarios, not so with LSPI. It might also come close to explaining why # 1 cyl seems to be a common theme because of slight differences in the flow/swirl characteristics of each cylinder. It might also explain why the knock sensors are unable to prevent pre-ignition due to the random nature of LSPI.

Looking at the web sites of the major oil companies, they seem to be all over this issue and all mention the new SN Plus, SP or GF6 standards. As the research is fairly recent the new compliant oils might not have reached all store shelves but they eventually will. In the meantime it's probably a good idea to look for SN Plus, SP and GF6 in addition to 229.51 spec.

decorily

I'm guessing this poll does not refer to Diesel engined GLCs which accounts for the vast majority of GLCs in most parts of Europe.

AVGLC

45k miles. This is the M264 and did not have catastrophic engine damage. Transmission level was checked and updated a year ago and everything seemed ok. Was wondering if other owners have seen this. This is looking down from the top on the back of the engine.