I feel for you for sure. Our 2016 GLC 300 is billowing smoke. Dealer reports low compression cylinder 1 and a possible cause is a cracked piston. 49K miles, 8mo out of warranty, corporate refused any consideration of exception, not even a loyalty discount. This was a dealer maintained vehicle except for 1 oil change done by me with dealer bought parts and a AAA installed battery. Dealer was more sympathetic and agreed to a buy back. Still a loss but a less painful one. I do value the dealership good faith but definitely lost all respect for the MB brand after our experience and reading all the posts. I expected to always own an MB as this is our 3rd (others C230 & CLK55AMG convertible, both were great). With MB corporate refusal for ANY consideration at all for this type of failure on a dealer maintained vehicle I will not speak highly of the brand or own one ever again. I hope one day this becomes a class action item. Thank you MBWorld for such a great platform for owners to learn from.

 

Sorry to hear and thanks for sharing your experience.

You have joined a long and growing group of consumers who have lost respect for the MB brand. MB seems to have lost respect for themselves, judging from reading your and others’ comments.

The strong pricing of today’s car market softens the pain, as you mentioned with the buyback.

What will your next vehicle brand be?

 

My '18 exhibits pre ignition way too often and I use only premium fuel. This in my opinion is a tuning issue which causes unnecessary cylinder pressure. Because of this, I added a Mercedes 100k warranty not expecting my engine to last long. I will be selling the vehicle prior to losing warranty coverage.

 

If you can actually identify knock, it might be a good idea to have your Dealer check for a malfunctioning knock sensor.

These days, I wouldn't own a primary modern car that's out of a bumper-to-bumper warranty. Imagine having to pay for a Ford seat motor, or (gasp) a Hyundai window motor.
That's why we traded our 2010 ML at 103,000 mi, 7 years, and our 2014 at 93,000, 7 years. That's just me. The '19 GLC will get a warranty next year.

 

Rafael Dianov rdianov@mbofelmbrook.com will get you handled.

 

I have 18 months left on my 2019 GLC300 SUV it'll be gone just at the end of that..

we traded a our 2010 Lexus RX350 it was a gem so we are going back to Lexus RX350 the the time comes.. it's a shame I love the GLC fit and body design buy why drive a ticking time bomb

 

If you still like the GLC you could still get the facelift GLC 300 with the M264 instead of the M274 you have. The next generation of GLC is coming out soon though, so the facelifts themselves won't be around for long (as in new vehicles... but you can always get a CPO if you really want to). Problem with the M264 is that there is not enough data to tell if that engine is also suffering the same issue. If you lost faith with Mercedes completely, understandably the Lexus may be the better choice for you. No matter what vehicle you ended up getting, I wish you happy and trouble-free miles.

 

Agreed that the M264 does not have enough time to know if it will grenade like the M274 does.

However, the M264 is descended from the M274, sharing foundational components. Noteworthy is the fact that MB changed piston part number for the M264, a sign that they may know a problem exists and action was taken to (hopefully) address it.

If it were my purchasing decision, I would stay away from the M264 until it has 5 years of production under its belt.

Even the reliable M276 took several years of production for MB to address chain tensioner and sensor oil leaks. MB is a low quality product manufacturer, sadly.

 

I am still scratching my head right now after they then introduced the M254 in the W206. I mean why don't they use the M264, it also can be paired with the 48V mild-hybrid system so that is not the reason.

 

I wonder if it is because they want to change for the sake of changing, or actually because it is the new C-Class so it has to get a new engine. I am just hoping it isn't actually because they identified a hidden fault in the M264 that we have yet known. Fingers crossed.

 

Have not decided on replacement. For now, Mrs decided on using our weekend mountain drive that doesn't get much use, 2012 Rubicon Unlimited AEV.

 

How many miles do you have on your GLC now?

 

i had the same issue with my c300 @51k miles and also contacted Mercedes’ and they refused to acknowledge their part in these pistons crack engine failures and it makes sense because if they do then they open the doors to all kinds of lawsuits. So to people who haven’t talked to Mercedes’ customer service yet : don’t waste your time . They won’t help, if you have a great relationship with your service department at the dealer you might get fifty percent off but the repair is over 16k dollars .

would everyone please please make sure you enter a complaint on the NHTSA website and emphasize how this failure was also a traffic safety issue . I sent the NHTSA a physical letter addressed to the administrator - it’s called a defect recall petition . Not many people know about it because the NHTSA doesn’t really mention it much but what it does is it guarantees by federal law that our issue gets investigated within a certain amount of time (believe it was 90 days) and if it is denied they have to give a reason why in the federal register (also by federal law) so it can’t be ignored at this point . I’m pretty much forcing them to investigate or claims at this point and it would be helpful if more of us go on the website and file the safety issue complaint as they will look for people with similar problems . I’m really confident this petition is going to help us out so keep your fingers crossed . I’ll let you guys know if any updates I receive .

 

Dunno if OP replaced yet or not but with prices of cars right now, it's probably best to just replace the engine then sell/trade to get out away from the engine series that is problematic. I found this article that describes differences between the M270/M274 engines and the newer M260/M64 engines.

Older: Mercedes M274/M270 1.6/2.0L Engine Specs, Problems & Reliability

Newer: Mercedes M264/M260 1.5/2.0L Engine Specs, Problems & Reliability

 

The M264 shares foundational components (crankshaft, connecting rods and more) with the problematic M274.

The M264 is too new to say with certainty that it won’t have problems as severe as the M274. Time will be the judge.

 

My 2018 C300 C Class Coupe M274 E20 GA 205.348.22-AU3 had a catastrophic engine failure at just over 10,000 Kms.
Diagnosis thus far is that Cylinder 1 Piston is cracked. Codes I was able to catch after the engine would no longer start and the check engine light was displayed. I had a OBD2 reader lying around after doing work on a friends car. Downloaded the full license for my car.

P030085 Combustion misfiring has been detected.
P030185 Combustion misfiring of cylinder 1 has been detected.
P030285 Combustion misfiring of cylinder 2 has been detected.
P030385 Combustion misfiring of cylinder 3 has been detected.

I had been on the road for less that 4 mins, when the car lost all power while accelerating from 40km - 70km. Prior to this no warning indicators had been displayed in the dashboard instrument cluster, no warnings were even displayed when the engine failed.

The vehicle is 90% driven within the CBD and surrounding suburbs within 15km.
During the last 6 months it is primarily driven in comfort mode due to increasing petrol costs.
The vehicle always receives premium petrol being Shell V-Power 98 (90% of the time) and BP Ultimate Unleaded 98 (10% the remainder) with no additional performance additives.
The vehicle is well serviced, very well maintained, in exceptional overall condition.
The never put under load or driven above 3800 rpm unless at operating temperature of approx. 95. deg C.Other premature failures include.

Exhaust Camshaft magnet o-ring failed @ 9,893 KM
Alternator Belt Pulley bearing Leaking leaking likely much before 10,688 when I picked it up.
Ticking noise on Cold Start at reported @ 4,425 Km which would remain until the engine had warmed.

I will be pursuing a claim with Mercedes Benz Australia under Lemon Laws and seek an entire engine replacement.

Whist my car is approx. 9 months outside of MB 2 year manufacture warranty Australian Consumer Law, specifically Consumer Guarantees for products stipulate all Australian businesses must provide a set of "automatic guarantees" regardless of standard manufacture warranties given or sold.

 

Yes, it's a pity the M274 has been plagued by so many fatal faults. The 2018 engine above with less than 10k miles is the latest production year with the lowest mileage I have seen reported on this site.

The M264 has some hand-me-down parts from the M274. Hopefully the newer M264 doesn't have the same "features" such as wrist-pin, piston and oil-in-harness failures the M274 has.

 

It has to be something random, US sales only of
GLC
2016 47,872
2017 48,643
2018 69,729
Plus C class
2016 77,167
2017 77,446
2018 54,829

Source https://www.goodcarbadcar.net/

We should see some pattern but we don't, not year or miles.

I would like to ask the owners whos engine failed, what was the oil change intervals you use? And what oil did you use ?

Im also 2018 GLC owner, and this bothers me a lot. I have sent a few oil samples to lab after 3.5K and 3.0K miles and results were not nice, after 3.5K miles oil viscosity was below min.
And its MB approved 229.5 Liquid Molly 5W40
At 3K result came back right on the edge.
I know cracked piston is more related to a temp in the cylinder, but oil helps reduce the temp.
Maybe injector injected too much or faulty spark plug. It has to be something leading to it.

 

I believe the Piston Part Number for the M264 has Changed (I.E a differrent piston) from that of the M274. I thought the wrist pins were no longer a issue after 2016.

 

M264 piston part number is different (changed) from M274.

The root cause of piston cracking in my view is design error by MB. The piston geometry, material choice and manufacturing process decisions by MB engineers result in piston cracking in the M274.

 

This thread has me seeing red. My 2019 hybrid GLC 350e with 56K miles on it just shuddered, overheated and died a week ago in Palm Springs (yes, it was 110 outside). I've been told broken plastic on coolant hose led to coolant hose split, basically a catastrophic coolant leak. I limped it to safety fearing the side of the road in the desert plus I had a cat in the car- neither of us would have fared well. Long story short, couldn't even get a tow on a Friday afternoon which I didn't find out for 3+ hours waiting (offloaded kitty to safety) in the 110+ heat by dead vehicle. Towed it in on Monday and found out Piston 3 and 4 are both damaged and I need a new engine. Quote from shop 18K. Tow to dealer (over 100 miles) quote from dealer 23K.

I'm sure it's not a huge deal to some people but this is financially devastating for me. Dealership offered to pay 9K to help with repairs- but now the service department is literally blaming me and telling me that I had to have it serviced at that dealership and they probably won't help me. I have had it serviced each 5k miles, but switched to a Mercedes shop on the last service because of two reasons- A) at same time my AC DIED with zero cooling, B) they wanted over 600 for the regular service and over 600 to evaluate the AC - $1200.00 for an oil change, air filter and estimate for AC repair. Down the street they did the regular service, diagnosed AC issue, repaired and had me out the door for about $1600 - estimate from MBZ >3K. When the AC went out I literally thought to myself, hmmm, this isn't a good sign. I couldn't have imagined this situation... not in my wildest dreams. I've been crying for a week with no end in sight of what the heck to do. I literally bought this car to feel safe and protected on the road. I can't really live without a car at all so I've already bought a different car and I'm just going to take a step at a time to get this broken piece of cr*p sold ASAP. Any other suggestions for getting them to take some responsibility greatly appreciated.

 

Sorry to hear of the experience, and glad you are safe. Sadly this is standard MB corporate and dealer treatment. Out of warranty = no joy.

It is something to keep an eye one for other owners - coolant hose splitting at <100k miles. Need to dig into the differences between GLC variants hybrid and non-hybrid. Looks like the GLC350e has the M254 petrol 4 cylinder with EQ Power+ hybrid system.

 

Do you have any documents or references with regards to the material of choice, manufacturing process ? Piston geometry is a little beyond my level but I will take what ever I can get at the moment. Will keep everyone posted with my claim as it progresses. I have provided a date MBauP should respond by before I pursue more formal options.

 

I don’t. Mass production pistons are generally cast aluminum, then machined.

Factors affecting piston cracking for a given combustion pressure:

- Aluminum chemistry
- Casting parameters: mold or die design. casting pressure, pouring temp and cooling process
- piston face and sides shape, ring groove depth and land thickness
- machining tool type, feed/speed and resulting surface roughness and dimensional tolerance
- surface treatment/plating presence, chemistry and thickness

Mercedes failed on this one.

 

Thank you for that Chassis. Appreciated.