Beware!! Apparently this is a very common issue, so common that the dealership was able to tell me what was wrong with my car without having to even look at it themselves.
First, a grinding noise would occur when turning over the car from a cold start. This would last only 2 seconds but was bone shattering when it would occur. At first this was intermittent and quickly became persistent whether it was a cold start or not. Then the car started to turn over very slowly (almost like the battery was dying) once the car turned over the check engine light came on. It threw two codes about cam shaft adjuster and something else. I have attached the codes to this thread.
I was finally able to get an appt at Mercedes and they came back to me with a bill of $6k and that’s to start, if the cam shaft plate shifted then it would much, much more expensive. They claim it should not have happened to this vehicle since it only has 60k miles but it is otherwise out of warranty and even though this is a common issue, reported from Mercedes dealership and research of my own, there isn’t a recall.
the $6k bill includes replacing the intake CAM shaft positioner with control valve. Replace timing chain and positioner and stop plug.
For me this is not worth it. This would be the second repair on the vehicle since owning 12/2019. The first repair took place at 40k and I don’t remember the exact name of the issue, but the cabin smelled of gasoline and of course something failed and it cost me $1k to fix and repair, naturally the replacement piece only came with a 1 year warranty. Again only 60k miles and if I have this much to replace, I can only imagine what will occur a year or two from now. Unfortunately I am giving up my GLC300 and won’t be buying a new one because someone from Mercedes informed me that he has seen this many times with many of the Mercedes that have the same engine as the GLC. I am devastated, absolutely devastated. I truly thought I was purchasing a great and reliable car after having to Lemon Law my former 2019 Infiniti QX50 for extreme safety issues concerning electrical failures and persistent sunroof issues.

Not that it's the same issue, but my GLC 350e needs a new engine at 56K miles. Quote from dealership $21-23.000. I've been crying and freaking out for a week. Car shuddered, overheat warning then loss of power. It's dead and I'm just completely devastated.

Crying in LA- I will NEVER trust mercedes again. I found a whole host of these GLC threads with engines needing to be replaced and other major terrible issues that MBZ doesn't take responsibility for. I don't know what I'll do, but wish you best of luck on this journey. Type your problem in the search bar- I saw this posted in another thread for sure- known problem!!!

Sorry to hear of the issue. Best wishes for a solution that meets your needs.

The M274 2.0L four cylinder is really a dud of an engine. Far too many major issues, most of them fatal, to list. Mercedes (non-) reliability strikes again. How can they design, manufacturer and sell such rubbish?

You're leaving out a lot of information. Was the car a CPO? If not, then you're playing with fire. Secondly, if the car is making terrible grinding noises when turning it over, why did you continue to turn it over? And why would you ever rely on a scanner for a noise you can actually HEAR? Don't put this on Mercedes, put this on amateur hour and not reading the room when the car is clearly trying to tell you something, but continue to drive it. You clearly don't know cars as you can't even remember what the issue was that left your cabin smelling like gasoline and costing you $1000. A car is like any other machine -- it can break. It will break, especially if not taken care of and ignored from a maintenance standpoint.

Not the brand, but sure. It's a known problem by Mercedes and they continue to build ****ty engines.

I'd be hitting up a few local German car repair shops. I'd bet they can find a used engine in a wrecked car and it would cost half of that amount.

That’s a great suggestion, I will look around to see what is out there. I appreciate this forum, it’s been helpful to discuss the issue/ look for a solution.

The fuel smell problem was likely the high-pressure fuel hose. Mercedes sent all owners a letter stating they would reimburse for the repair. They redesigned that part and took ownership of it.

Same here engine failure in 2021 GLC 300 50k. Distraught!!

Same issue mechanical engine failure in 2021 GLC 52k Distraught

Sorry to hear of this. It is not acceptable and distressing, I can imagine. Please keep us updated on the feedback from your dealer. Best wishes for the best possible outcome.

​​​​​@MrsLady yes, we'd like to learn specifics.
It would help if you could show a (redacted) copy of your Repair Order when it's available.
Until then, yes, keep us updated.