Mercedes-Benz GLC 300 2020

The contact owns a 2020 Mercedes-Benz GLC300. The contact received notification of NHTSA Campaign Number: 21V354000 (Back Over Prevention, Electrical System) however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure. Parts distribution disconnect.

The contact owns a 2020 Mercedes-Benz GLC300. The contact stated that while driving at an undisclosed speed, the panoramic roof unexpectedly shattered. There was no warning light illuminated. The vehicle was taken to the dealer, where it was determined that the panoramic sunroof and the sunroof protector needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure, and a case was opened. The approximate failure mileage was 53,035.

Water condensation within the driver side headlight which caused the complete headlight unit, control unit, and module to fail. This is a huge safety issue due to unable to operate vehicle safely during the when it comes to making left turns due to no signal indicator and a safety issue/hazard when driving at night. The issue has been inspected with a local dealer and with corporate being aware of the manufacturer defect. There were no indicators nor warning lamps prior to this issue.

With approximately 57,500 miles, the car began idling roughly, misfiring and losing power. The dealership has diagnosed it with a cracked cylinder head which will require a replacement at a cost of $9,765.00. The dealership indicated this is a common issue with the M264 engine (rear wheel driver) in the GLC300 and the M260 engine (the front wheel drive version) has already had a service extension for 15 years/180,000 miles. This type of failure should not occur at this mileage or even significantly more.

Driving slowly through a parking lot and had to stop for pedestrians. When the path was clear, the car would not accelerate. It only idled forward and slowly reached about 5 mph. Stepping on the accelerator pedal gave no response after repeatedly trying to accelerate. No warning lights came on to alert me of a problem. I was able to pull into a parking spot and after shutting off the ignition and turning back on, the throttle responded as normal. This was a very scary situation but at least it happened in a parking lot.

The contact's wife owns a 2020 Mercedes-Benz GLC300. The contact stated that while his wife was driving at an undisclosed speed, the vehicle stalled. The vehicle was towed to the dealer and diagnosed with ignition failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired and remained at the dealer. The manufacturer was made aware of the failure but declined to buy back the vehicle and offered a two-year service plan for a free oil change per year. The failure mileage was approximately 30,000.

The engine is failing, I was on my way to drop my [XXX] off at daycare when suddenly my car went above and stayed above 5rpms meanwhile I was only able to drive 8mph. This caused a tractor trailer swerving into on coming traffic, if he didn’t my toddler and I would have been killed. As I managed to pull off and call my husband to get the baby the engine started making a strange clicking noise. There’s maybe 60,000 miles on this vehicle none of this should be happening. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2020 Mercedes-Benz GLC300. The contact received notification of NHTSA Campaign Number: 21V354000 (Back Over Prevention, Electrical System). The dealer was notified of the recall and informed the contact that the recall repair would be performed over-the-air (OTA). The contact then called the manufacturer and was informed that the update was not available; he was informed that there was a waiting list and that he would receive a notification when the update for the vehicle was available. The contact had not experienced a failure. Parts distribution disconnect.

The contact owns a 2020 Mercedes-Benz GLC300. The contact stated that while operating the vehicle, the 12-Volt battery warning light remained illuminated. The contact stated that while driving at various speeds, the vehicle shut off. The failure also occurred while driving on a busy freeway. The vehicle was towed to the local dealer who diagnosed that the STOP/START button was faulty and needed to be replaced. The STOP/START button was replaced but the failure persisted. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was 40,000.

The sunroof of our car shattered by itself when we were driving on a city street. There was no projectile that caused the sunroof to shatter and the dealership was able to confirm that. But the dealership and the company are unable to say for certain why this happened and whether or not this will happen again. The incident caused glass to fall on all our passengers and the sound of the glass shattering during driving really scared us. We are concerned for our safety and even more concerned that Mercedes is unable to diagnose why this happened and are not able to say for sure that it would not happen again.

The contact owns a 2020 Mercedes-Benz GLC300. The contact stated while attempting to reverse, the back over prevention camera displayed a blank screen. The vehicle was not taken to an independent mechanic or dealer to be diagnosed. The contact stated that the failure had occurred on several occasions. The vehicle was repaired. The manufacturer was notified of the failure, and informed the contact that the VIN was not under recall for the failure. The contact related the failure to NHTSA Campaign Number: 22V232000 (BACK OVER PREVENTION); however, the VIN was not included in the recall. The contact was referred to the NHTSA Hotline for assistance. The failure mileage was 35,886.

The contact owns a 2020 Mercedes-Benz GLC300. The contact stated while driving at an undisclosed speed during a rainstorm, the contact became aware that there was water inside the headlight assembly. Later, the contact stated that while driving at night, the headlamps were not functioning as needed. The contact stated that after a visual inspection, the driver’s and passenger’s side indicators were not functioning. The headlamp warning light was illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the headlight assembly. The vehicle was not repaired. The manufacturer was notified of the failure but provided no assistance. The failure mileage was 65,000.

I was driving and stopped car to make a turn waiting for incoming traffic to clear. When I went to accelerate after traffic cleared, the car would not go above 0.5 miles per hour. I made sure the gear had not shifted to neutral, it was on comfort drive. I changed to sports drive and the car still would not accelerate above 0.5 miles. I was now stuck in the middle of intersection with incoming traffic, so I tried to reverse. The car reversed no faster than 0.5 miles per hour. I turned car off and back on, and acceleration then worked. Very scary. I was lucky incoming traffic avoided me. Big safety hazard. Dealership so far has not been able to replicate the issue, but I read other blogs where people experienced a similar event.

My check-engine light recently illuminated, and diagnostic testing identified fault code P06DA00, relating to the oil pump control valve circuit. I have been quoted over $5,000 to replace the oil control valve and oil pump harness. I was quoted the following by Mercedes Servuce in Manchester, NH- Oil Pressure Regulator Valve: need to remove lower oil pan only to access oil control valve and replace the valve and sub harness. $5013.52. This is a known issue. My vehicle has been well maintained, and I have been advised that it is otherwise in excellent mechanical condition. I intend to keep and drive this vehicle for many more years, which makes it particularly disappointing to encounter a repair of this magnitude for a component that is not considered a routine maintenance or wear item.

The contact owns a 2020 Mercedes Benz GLC300. The contact stated that while driving at approximately 60 MPH, the front of the vehicle was vibrating and shaking violently. The vehicle was taken to the dealer where they informed the contact that the tires were balanced and needed to be rotated. The vehicle was repaired however, a month later the failure persisted. The vehicle was taken back to the dealer where it was diagnosed that the rear tires needed to be replaced. The vehicle was repaired but a few months later the failure recurred. The vehicle was taken back to the dealer where it was diagnosed that the front tires were worn unevenly and a four-wheel alignment was needed. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 450.

The contact's son owns a 2020 Mercedes-Benz GLC300. The contact stated that when the vehicle was taken for the State Emissions Inspection, the vehicle failed the inspection due to a defective "smoke cannister". The contact stated that after the vehicle failed the inspection, the "check emissions" message appeared on the instrument panel. The contact called a dealer and was advised to purchase and install the smoke cannister. The vehicle was taken to an independent mechanic who installed a new smoke canister; however, the failure reoccurred, and the vehicle failed the State Emissions Inspection test again. The vehicle was taken back to the dealer where the vehicle was diagnosed with a defective smoke canister and valve. The vehicle was not repaired. The manufacturer was informed of the failure. The failure mileage was unknown.

I have had issues with squeaky, very loud noises at slow speed and reverse braking. I have had this issue since I purchased this vehicle. I have brought it in a few times to have 2 different dealers fix the noise as I believe it is a safety issue as well. They said this is a common issue with GLC that they have noises while braking but there is no fix. I had an advisor drive the vehicle and witness loud squeaky noises while braking. Spending a lot of money on this vehicle, and Mercedes should fix this issue. I believe the brake system falls under lemon law and Mercedes should do something to mitigate the issue. The brake pads were okay upon inspection, but pretty soon I will have to pay a lot of money to replace pads at my own expense when the brakes, pads, rotors, etc themselves should be replaced and fixed at Mercedes expense.

Premature oil pump failure on a 2020 Mercedes-Benz GLC 300 with 71,000 miles. The check engine light illuminated on December 29th, 2025 and with no other warning symptoms. The vehicle has been maintained properly, including regular visits to Mercedes-Benz dealerships. The oil pump is a critical engine component that should not fail at this mileage. It has been recommended to not drive the vehicle without repairing as oil can leak onto a hot engine. This issue has been confirmed by a Mercedes dealer. Mercedes-Benz has offered 1,000 in goodwill on a 7,400 repair, which is unreasonably low given the nature of the failure. The dealer is advocating for higher goodwill, but corporate has refused to escalate or provide a breakdown of the offer. This failure appears to be a premature mechanical defect rather than normal wear, and I am filing this complaint to request federal tracking and review.

The contact owns a 2020 Mercedes-Benz GLC300 equipped with Goodyear Tires, Tire Line: Eagle Sport All Season, Tire Size: 255/45/R20, DOT Number: NE12JU1R1021. The contact stated that within a year of purchasing the vehicle brand new, he noticed that there was significant amount of rubber coming off the outer side of the front passenger's side tire. The contact stated that the failure was moderate on the front driver's side tire. The contact stated that the vehicle was taken to the dealer, where the front driver's side tire was replaced twice due to the failure. Additionally, the front passenger's side tire was replaced three times; however, the failure persisted. The contact stated that upon investigating the failure online, he learned that the steering knuckle might be damaging the tires. The dealer was notified of the failure. The vehicle was not diagnosed or repaired. The vehicle and the tire failure mileage were approximately 6,000.

The contact owns a 2020 Mercedes-Benz GLC300. The contact stated that while driving at an undisclosed speed, the engine misfired. In addition, the check engine warning light was illuminated. The contact was turned off and restarted the vehicle. The contact stated that the vehicle drove as needed. The contact stated that the vehicle was taken to an independent mechanic however, the failure was unable to be duplicated. The vehicle was not repaired. The contact stated that the failure occurred intermittently for several months. The vehicle was taken back to the independent mechanic where it was diagnosed with a failed engine vent seat and the engine vent seat needed to be replaced. The vehicle was not repaired. The contact was advised to take the vehicle to the dealer. The vehicle was taken to the dealer where it was diagnosed with a failed engine vent seat and the engine vent seat needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and a case was filed. The failure mileage was approximately 25,000.

On August 15, 2025, I was driving my Mercedes-Benz GLC 300 4MATIC on the freeway under normal conditions. Without any warning lights, error messages, or prior signs of mechanical issues, the vehicle suddenly and completely lost power. The accelerator pedal became unresponsive and felt locked, and the vehicle came to an abrupt stop in the middle of an active freeway, in the second lane from the left. I had no ability to control or prevent the stoppage. This unexpected power loss directly led to a rear-end collision. The vehicle behind me sustained severe front-end damage, including airbag deployment. My passenger and I were in shock and suffered whiplash and physical injuries, with pain and bruising following the impact. I suspect the most likely causes may be an Electronic Throttle Control failure or a false activation of an Active Safety System. I opened a case with MBUSA (Case #16298894) immediately after the incident, but I have not received any updates on the investigation. This was a dangerous and life-threatening failure, and I am deeply concerned that it could occur again to other drivers if not addressed.

The contact owns a 2020 Mercedes-Benz GLC300. The contact stated that upon driving through an intersection at 40 mph, another vehicle had run a stoplight. The contact swerved in an attempted to avoid the vehicle, however, she had hit the vehicle's rear driver side tire weld. The contact stated that the driver-side airbag did not deploy upon impact; however, the passenger-side airbag, where her mother was seated, did deploy. The Mercedes-Me app automatically called 911 and the contact initially declined medical attention at the time. A police report was filed. Due to the failure, the vehicle was towed to an independent mechanic. The next day, the contact was referred by her doctor to a hospital where they performed a cat scan and x-ray. The contact tested positive for Covid-19 the following Monday and believed it was as a result of the hospital visit. The manufacturer was notified of the failure and upon her own research, the contact discovered NHTSA Campaign Number: 21V354000(BACK OVER PREVENTION, ELECTRICAL SYSTEM). The vehicle remained in the possession of the independent mechanic and had yet to be repaired. The failure mileage was unknown.

It took a few minutes to be able to completely turn left out of a shopping center while waiting in line. When finally able to turn left, the car stalled into what appeared to be neutral where I had no control to increase speed and was turning very slowly. Oncoming traffic from both ways were coming and luckily stopped on-time. I had to turn off the entire car and restart in the middle of the road in order to be able to drive again. There could've been a massive collision if cars were not paying attention on both sides. Note that the car was NOT in neutral at the time and was in drive the entire time. This same incident also happened over a year ago but thought it was something I could've done wrong or was a one-time thing. Now that it's happened twice confirms that there is something wrong with the car. The car did not indicate a power failure or warning lights during this incident. I have an appointment with Mercedes on 4/25 to get this looked at. This has been reported on other models from other car owners but we have never seen a recall. This is a serious malfunction and could've gotten myself or others killed. I do not feel safe driving this car unless it is fixed.

Dear Sirs: I own a 2020 GLC300W Mercedes SUV. As of this date, It has stalled 5 times while driving on the highway and on the roads within an 8 month period. Throughout this period, I have taken the vehicle to the Mercedes dealership in Riverside, CA three times to have this inspected. After their first inspection, the dealership claimed that the problem was due to a recall on a computer software update needed. However, the vehicle stalled two more times while driving on the highway. After the second inspection, the dealership claimed the problem was due to a bad throttle actuator and charged me $2000 for the repair. Two months later, the vehicle stalled on the road once again. Currently, the dealership is inspecting the vehicle for a THIRD time. I have viewed your NHTS website and came across NHTSA campaign number: 23V445, Problem Description: Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2021-2023 C-Class, E-Class, S-Class, CLS, SL, GT, GLC, GLE, GLS, and G-Class vehicles. Please refer to MBUSA's recall report for specific vehicle details. The fuel pump may shutdown, which can result in a loss of drive power." I believe this is the cause of my 2020 Mercedes doing the exact same thing, however the 2020 model is not listed in this recall. Please investigate this as this may be fuel pump issue applies to 2020 models.

My 2020 Mercedes-Benz GLC 300 experienced a complete engine failure at ~51,000 miles, shortly after a major repair for a known defect. Initially, the vehicle showed a misfire on cylinder #3, which was diagnosed at RBM of Alpharetta as low compression due to valve seat damage, matching MB TSB LI01.30-P-072328. The cylinder head was replaced in Aug 2025. About two months later, while driving under normal conditions, the vehicle made a loud cranking/knocking noise and completely stalled in traffic without any check engine light or warning. This sudden stall posed a serious safety risk. The vehicle was towed to the same dealer, who has now diagnosed the engine as fully seized and recommended a complete engine replacement. I had also completed the 50,000-mile scheduled service at the same dealer shortly before this failure. Despite this being clearly linked to a known design defect, Mercedes-Benz USA has declined to provide further assistance or goodwill coverage. I am reporting this to highlight both the mechanical failure and the safety risk—this engine seizure occurred without any prior warning lights and could have resulted in a crash. I believe this reflects a systemic failure with the M264 engine in GLC 300s, affecting vehicle reliability and road safety. MBUSA has not provided a written explanation for their denial. I am concerned this issue may affect other GLC 300 owners and deserves investigation or recall consideration.

On Saturday October 5th at roughly 8:30 p.m. heading West on I-94 near battle creek, MI, the glass sunroof on our Mercedes suddenly exploded out and shattered. We were traveling at 75 mph with little surrounding traffic and no over-head obstructions. It took a second to re-gain control of the situation and slow down to a stop. We had the sun-shade closed, saving us from glass shards raining down from the exploded sunroof. The following Monday morning, Oct 7th around 9:00 a.m., we called Mercedes about the issue. They were indifferent and offered no assistance. They pointed out that our MY2020 with 29,711 miles on the odo was not covered under warranty for the sunroof shattering and that we would have to deal with our insurance company. They also informed us that they would not have any rental cars available during a repair until at least December. We mentioned that there was signs on the internet of class-actions against Mercedes for similar sunglass explosions to which they quickly responded with - not on MY20 300 GLC. We did get the sunroof replaced through our insurance. Anecdotely, when we took it into the glass repair shop, they had just did another one, similar situation the week before. This could have been tragic. Glass shards could have been everywhere. The only reason the sunscreen was deployed was that we had our baby granddaughter in the car only 1 hour earlier. Otherwise, that screen would have been open and the glass would have rained down on everyone in the car.

My 2020 Mercedes-Benz GLC 300 triggered check engine light with code P06DA (engine oil pressure control) at 40,000 miles. The failed component is an oil pressure control sensor/solenoid worth approximately $200. However, due to Mercedes-Benz's engine design (M264 engine), the entire engine must be removed from the vehicle to access and replace this part. Repair estimate from authorized Mercedes-Benz dealership (Mercedes-Benz of Stevens Creek): $8,391. SAFETY CONCERN: Loss of oil pressure can cause catastrophic engine failure while driving. Engine seizure at highway speeds poses serious risk of loss of vehicle control, potential accident, and harm to occupants and other drivers. This is a known, widespread design defect affecting Mercedes-Benz vehicles equipped with M264/M274 engines across multiple model lines: GLC 300 (2019-2023) C 300 (2019-2023) E 300 (2019-2023) GLC 43 AMG, C 43 AMG GLB 250, A 220, CLA 250 Mercedes-Benz's own authorized dealership confirmed they are "seeing this issue more and more." Despite awareness of this widespread defect, Mercedes-Benz has not issued a recall or Technical Service Bulletin. The design makes repair financially prohibitive ($8,000+), meaning many owners continue driving with compromised oil pressure — creating an ongoing safety hazard on public roads. Mercedes-Benz refused to repair under goodwill, then denied repurchase after 30-day review. They have left consumers with no remedy for a known safety-related design defect. I am requesting NHTSA investigate this as a safety defect affecting potentially hundreds of thousands of vehicles.

The engine in my 2020 Mercedes-Benz GLC 300 suddenly malfunctioned while driving on two separate occasions. The vehicle began shaking violently and lost power without warning. I could not accelerate and had to pull over immediately. I turned the vehicle off and restarted it to regain limited driveability. On the second incident, the power loss was so abrupt that it felt as if I had been rear-ended. I feared the vehicle would stall in traffic and cause a crash. Following these events, the check engine light remains constantly on. The dealer inspected the vehicle and confirmed excessive valve leakage into the exhaust system, requiring a complete cylinder-head replacement. They warned the failure will worsen and could result in sudden power loss again. This defect poses a serious safety risk. If the power loss occurs while merging or at highway speeds, it could easily lead to a rear-end collision. The vehicle has relatively low mileage for such a severe internal engine failure, and I have learned that other owners of this same engine have reported similar issues. Sudden stalling or loss of acceleration places occupants and other drivers in danger. There were no warning messages prior to the failure, and the problem has recurred. The vehicle is available for inspection, and the defect has been confirmed by a Mercedes-Benz service center. This appears to be a mechanical defect in the engine design, potentially involving valve seat failure. An investigation is needed to determine if this issue is widespread and whether a recall or manufacturer action is required to prevent accidents or injuries.

I am the owner of a 2020 Mercedes-Benz GLC300 with the M264 engine. I am hoping that you can assist me with a widely reported, systemic defect: the premature failure of the master cylinder, regardless of vehicle mileage. This issue is extensively documented by numerous owners of the 2020 and 2021 GLC300 models across various public forums, including Reddit and dedicated GLC owner communities. I took my vehicle to Mercedes dealearship for annual service and an intermittent check engine light. The dealership informed me it was a spark plug issue. Once repaired the check engine light went on permanently and the car hesitated as if it would turn off. I brought my car in for service and was told that it was a master cylander failure of the engine. Known Defect: The defect is so widespread that it indicates a manufacturing or design flaw. Corporate Refusal: Mercedes-Benz corporate has failed to acknowledge this systemic issue publicly or initiate a recall. Local Acknowledgment: When engaging with Mercedes-Benz of Paramus, Service Manager Ben Wright acknowledged both the existence of the issue and Mercedes-Benz's corporate awareness of the defect, yet confirmed the lack of a formal recall. Repair Cost & Offer: Following the failure, I was presented with a $12,000 repair bill for parts and labor. The only offer of assistance from corporate was a minimal 20% discount, still forcing me to pay a final cost of $10,620 for a repair that should be covered under a mandatory recall. Unfortunately, I was out of warranty by 1 year and 8,000 miles. This refusal to address a known mechanical flaw is unacceptable, especially given the significant financial burden placed on owners for a defect acknowledged internally.

Problem (repeat failure / prior warranty replacement): This vehicle has a recurring headlamp defect involving moisture ingress into the headlamp housing/connectors, causing electrical shorting and warning messages, with risk of headlight failure. Mercedes-Benz replaced this same headlamp under warranty in 2021 for the identical issue (moisture/shorting). The defect has recurred on the same vehicle.Recent verification: On Oct 13, 2025, the dealer (Mercedes-Benz of North Palm Beach) observed visible condensation/fogging in the lamp and confirmed it matches the prior failure that was repaired under warranty. Pattern affecting other owners: There are multiple consumer complaints in NHTSA’s database describing condensation, moisture intrusion, shorting, and headlamp malfunctions on GLC vehicles, including the 2020 model year. This indicates the issue is not isolated. Related recalls / known condition: NHTSA Recall 22V261 (GLC) identifies headlamp moisture/connector sealing problems leading to lighting failure. While my VIN is not currently included, the failure mechanism is the same: moisture → short → potential loss of headlight illumination. There are also GLC lighting recalls addressing exterior lighting malfunctions, underscoring that lighting faults on this platform are safety-relevant. Safety risk: Headlamp moisture/shorting can disable exterior lighting, reduce nighttime visibility, and increase crash risk. This is a repeat, safety-related defect previously repaired by Mercedes-Benz that has returned. Requested action: Please investigate this headlamp moisture/shorting defect on the 2020 GLC as a recurring safety problem, consider expanding applicable recall/remedy coverage, and direct the manufacturer to provide a durable fix and appropriate remedy for affected vehicles.

What component or system failed or malfunctioned, and is it available for inspection upon request? The Forward Collision Avoidance / Active Brake Assist (Automatic Emergency Braking) system failed by falsely identifying a non-existent threat and initiating uncommanded emergency stopping. The vehicle and its onboard control modules are fully available for physical and diagnostic inspection upon request. How was your safety or the safety of others put at risk? While traveling at approximately 35 mph, the vehicle suddenly executed maximum emergency braking with zero warning and no preceding obstacles, vehicles, pedestrians, or road hazards present. The violent deceleration caused maximum seatbelt restraint locking force, resulting in sudden physical impact trauma to a 6-month pregnant passenger and acute dizziness/disorientation for both occupants. This malfunction creates a severe, immediate risk of high-speed rear-end collisions from trailing traffic and unexpected loss of vehicle control. Has the problem been reproduced or confirmed by a dealer or independent service center? Not yet. The vehicle has not yet been serviced or inspected by a dealer or independent service center following this event. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? No. Neither the manufacturer, police, insurance representatives, nor third-party investigators have inspected the vehicle or component since the incident occurred. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? There were no warning lamps, error messages, chime alerts, or functional symptoms prior to the sudden brake activation. The Active Brake Assist system triggered immediately without prior warning.

While driving on the highway I began to hear an unusual amount of wind noise inside the car. I thought the sound was coming from the sunroof, though it was completely closed. I pushed the button to confirm it was sealed, but the noise continued. Shortly after, I heard a loud cracking sound followed by a sudden pop. I looked in my rearview and saw something flying but didn’t immediately recognize what it was. I pulled over to inspect the situation and discovered that the entire exterior trim panel between the windshield and sunroof had detached. Another driver, who had been behind me, also pulled over after being struck by the debris. Thankfully, there were no bodily injuries, but this incident could have resulted in a serious accident. A large, fast-moving piece of trim flying off a vehicle at highway speeds presents a significant danger to other drivers, especially if they try to swerve to avoid it. I took my car to a Mercedes-Benz dealership for inspection and potential repair. I informed the service advisor that I had seen documentation of a recall involving the same issue, detachment of the sunroof panel on vehicles of the same make, model, and year as mine. However, I was told that my vehicle was not eligible for the recall based solely on its VIN and that Mercedes would not cover the cost of repairs. This is not a typical wear-and-tear issue. Structural components of a car should not randomly detach, especially on a vehicle that is only 5 years old and has been properly maintained. It is extremely concerning and, in my opinion, negligent for Mercedes-Benz to be aware of this defect and yet fail to extend the recall to all affected. The advisor acknowledged this issue was likely due to a problem with the adhesive used to secure the panel, something he said he had seen happen on other vehicles. Despite this, I was told I would be fully responsible for the repair costs. There were no warnings or signs this would this happen, the panel detached suddenly.

•Jan 2025, while the car owner was driving her GLC300, a warning light came on, the car shook and then shut down. AAA tow truck suggested Green’s Garage as an approved nearby repair shop. Car was towed there and repaired for approximately $450.00. •[XXX], late afternoon, the same problem arose but the car did not shut down. The car owner drove the car home and the car was dropped off at Green's Garage (GG) on the morning of May 27. Late that afternoon, GG called us to tell us the problem is not related to the January repair…Even though the symptoms were exactly the same as January with the exception of the car not shutting down. GG later stated the new problem is related to the spark plugs and that the cost to repair would be about $450.00. We agreed. •The next day (Wednesday) late in the afternoon GG called us to tell us that they found an additional problem. One of the fuel injectors was leaking. To fix the fuel injector plus the spark plugs would cost about $1,300.00. We agreed. •The car owner picked up the car late Thursday afternoon. Nothing was fixed, the engine warning light immediately came back on and the engine shook, so we have formally disputed the $1,300.00 credit card charge with our bank. [XXX] took the car on June 4 at 9:00 AM to Mercedes of Coral Gables for a pre-arranged $360.00 diagnosis. On June 5 we were informed that the engine and transmission mounts collapsed for a repair charge of $2,518.00. Also, the cylinder head valve seats are leaking and need replacing for a charge of $11,757.00. Total $14,275.00. Mercedes Benz should pay for this. Our car is a 2020 model with only 63,000 miles, but the problems started at less than 60,000 miles. We have read that this problem with this engine has existed since 2024 or earlier and that Mercedes Benz refuses to acknowledge the situation or pay for the repairs. It is dangerous to drive this car. Mercedes should be held responsible for all repairs and and accidents caused by this malfunction. INFORMATION R

Some M264 Engines are predisposition to premature cylinder head failure, this issue can cause significant misfire issues. It also leads to a costly repair. We experienced issues with a P219D code , we had the coils and plugs replaced on a 2020 GLC 300 with 38.5 k miles. We assumed that this issues with a misfire and check engine light were corrected. My wife was turning onto [XXX] in Pascagoula MS last week, the car misfired and stalled with cars and semi trucks rapidly approaching, several cars had to slam on breaks and this issues almost caused a significant wreck. She had to pull over to gain her composure, the car would not over above 2k RPMs. I showed up and was able to to restart the car , I immediately drove it back to the repair shop. The shop bore scoped the #2 cylinder, the valve seating is significantly damaged, thus causing a significant loss of engine power / misfire in cylinder 2. I reached out to Mercedes Benz USA and was advised to take the GLC300 to the dealer that sold us the car. At present the is being evaluated by the MB dealer. MB USA is well aware of issues regarding cylinder head failure. There is actually a low mileage GLC 300 at MB of Mobile with the same problem as our MB. They have sent out service bulletins to every MB Dealership in the US regarding this issue. Likewise they have extended the warranty on several MB models that share the same engine that are mounted for front wheel drive cars, M260 engine. The M264 is an identical engine that is mounted for rear wheel dive vehicles. It is beyond obvious that a significant loss of engine power poses a threat to the driver/occupants and other vehicles/occupants on the road. MB USA is well aware of this issue with their engines. Not only do they have a service bulletin regarding this matter , they have repair protocols which include a cylinder head replacement. This is a consumer and safety issue that needs to be corrected on applicable GLC 300 models. INFORMATION REDACTED PURSUANT TO THE FR