Owners have filed 92 complaints
about the 2021 Mercedes Benz GLC 300 with NHTSA between 2021 and 2026.
The largest single group is the engine & cooling.
Across this model's run it ranks 7 of 8 worst.
The letter says how bad. This says what kind — whether this year drew
an unusual number of complaints, unusually dangerous
ones, or failures that arrived unusually early.
The dashed ring is 50 — the national norm. Further out is worse.
Complaint volume — 59
Against the median year of the Mercedes Benz GLC 300. 50 means typical for this
model; 100 means roughly double.
Severity — 17
3.3% of these complaints
involved a crash, fire, injury or death, against a national rate of
9.7%.
Early failure — 100
73% of failures with a mileage on record happened under
36,000 miles, against a national rate of
29%.
How 2021 compares with every other Mercedes Benz GLC 300
Odometer readings owners gave when they filed. About half of all
complaints include one.
Under 1,000 miles
533.3%
1,000 – 9,999 miles
213.3%
10,000 – 24,999 miles
16.7%
25,000 – 49,999 miles
426.7%
50,000 – 74,999 miles
16.7%
75,000 – 99,999 miles
213.3%
When owners complained
A spike years after the car went on sale usually means a part wearing
out on schedule across the whole fleet — the kind of pattern no single
owner can see from inside their own car.
Mar 2021peak 5Sep 2026
Complaints that involved harm
Reports where the owner recorded a crash, a fire, an injury or a death.
Cherry Hill, NJFire
UNKNOWN OR OTHER
While the vehicle was being operated normally, it caught fire. We were driving on a summer day in August. Conditions were humid, with temperatures in the mid-80s. The vehicle was on the return leg of an approximately 30-mile drive. Traffic was somewhat heavy, with speeds generally below 20 mph and occasional stops. We first noticed a slight burning smell, followed shortly afterward by a distinct puff of white smoke coming from under the hood on the passenger side, near the windshield. We immediately decided to stop the vehicle and get out. Within approximately 30 seconds, we observed the first visible flames. Within about one minute, the fire had spread rapidly and the vehicle was engulfed in flames. By approximately 3½ minutes, the entire front half of the vehicle had been destroyed by the fire. Parts of the vehicle were blown off during the fire, with some debris traveling across the roadway and into the nearby woods. Fortunately, there were no injuries because we recognized the danger and exited the vehicle quickly.
NHTSA complaint #11760363 — an unverified report by a vehicle owner.
Laguna Niguel, CAFire
UNKNOWN OR OTHER
Driving short distance home when the bottom of Mercedes GLC 300 caught fire without warning or notification. I was unaware when a good Samaritan screamed out your car is on fire. Pulled over and she helped me out. Seconds later the car exploded into flames and the car was demolished.
NHTSA complaint #11631534 — an unverified report by a vehicle owner.
at 35,000 milesFarmington Hills, MICrash
ENGINE
The contact owns a 2021 Mercedes Benz GLC 300. The contact stated that while driving at various speeds, the vehicle would lose power and fail to accelerate upon the depression of the accelerator pedal. The check engine light would appear on the instrument panel. Despite the failure, the vehicle would resume normal operation upon restart of the engine. The vehicle was initially taken to a dealer but the dealer could not duplicate the failure. The failure worsened over time which resulted in the contact being rear-ended by another vehicle. The air bags did not deploy upon impact and the contact was not injured. A police report was filed and the contact was able to drive the vehicle away from the scene of the accident. The vehicle was taken to various dealers and independent mechanics where each diagnosed the vehicle with a defective cylinder head. The manufacturer was notified by the dealer about the failure and the manufacturer agree to cover half the cost of the repair. The vehicle had yet to be repaired. The failure mileage was approximately 35,000.
NHTSA complaint #11607115 — an unverified report by a vehicle owner.
The most recent complaints
In the owners' own words, exactly as filed with NHTSA.
Marietta, GA
EXTERIOR LIGHTING
I own a 2021 Mercedes-Benz GLC 300. The vehicle developed moisture/condensation in the headlamp, and the affected headlamp subsequently failed. I took the vehicle to RBM of Alpharetta, an authorized Mercedes-Benz dealership. I was advised that corrosion was found in the affected headlamp and that the headlamp assembly requires replacement. On September 8, 2026, the dealership provided a repair estimate of $3,387.33. The vehicle had approximately 84,769 miles. Mercedes-Benz previously issued NHTSA Recall 22V-261 / Campaign 2022050005 for certain 2021 GLC-Class vehicles because headlamp electrical connections may not have been sufficiently watertight, allowing moisture intrusion that could cause headlamp failure. My vehicle is the same year and model and is experiencing headlamp failure involving moisture and corrosion, but Mercedes-Benz states that my VIN is not included in the recall population. Mercedes-Benz Customer Care opened Case 23963515 and has declined coverage to date. I am concerned that my vehicle may be experiencing the same or a substantially similar moisture-intrusion defect as vehicles covered by Recall 22V-261. A failed headlamp reduces nighttime visibility and presents a safety concern. I am requesting that NHTSA review whether similar headlamp moisture intrusion, corrosion, and failure may be occurring in additional 2021 Mercedes-Benz GLC 300 vehicles outside the original recall population.
NHTSA complaint #11763616 — an unverified report by a vehicle owner.
Orlando, FL
EXTERIOR LIGHTING
My vehicle is experiencing moisture intrusion caused by a defective headlight housing seal. The water intrusion has resulted in a short circuit and failure of the turn signal module within the headlamp assembly. I am aware of NHTSA Safety Recall 22V-261, which addresses a substantially similar defect involving inadequate watertight sealing of the headlamp assembly that can allow moisture intrusion and lead to headlamp electrical failure. My vehicle is experiencing the same type of moisture intrusion and resulting electrical failure described in that recall. Because this failure appears consistent with the known safety-related defect identified by NHTSA, I am requesting that the vehicle and affected headlamp assembly be evaluated for recall-related or manufacturer-assisted repair rather than treated solely as a routine out-of-warranty component failure.
NHTSA complaint #11763491 — an unverified report by a vehicle owner.
South Euclid, OH
EXTERIOR LIGHTING
My 2021 Mercedes-Benz GLC 300 is not currently included in NHTSA Recall 22V-261 / Mercedes-Benz Campaign 2022050005, but my vehicle is experiencing substantially the same defect described in that recall. Moisture/water entered the left headlamp assembly/electrical connection, resulting in condensation/water accumulation and damage/corrosion around the headlamp electrical module/connector. The headlamp system subsequently malfunctioned. Recall 22V-261 describes a condition where the headlamp electrical connection may not be watertight, allowing moisture ingress and potentially causing headlamp failure. My vehicle appears to exhibit the same condition even though my VIN is excluded from the recall population. I am requesting that NHTSA review whether the affected population for Recall 22V-261 may need to be expanded.
NHTSA complaint #11762288 — an unverified report by a vehicle owner.
South Euclid, OH
ELECTRICAL SYSTEM
My 2021 Mercedes-Benz GLC 300 is not currently included in NHTSA Recall 22V-261 / Mercedes-Benz Campaign 2022050005, but my vehicle is experiencing substantially the same defect described in that recall. Moisture/water entered the left headlamp assembly/electrical connection, resulting in condensation/water accumulation and damage/corrosion around the headlamp electrical module/connector. The headlamp system subsequently malfunctioned. Recall 22V-261 describes a condition where the headlamp electrical connection may not be watertight, allowing moisture ingress and potentially causing headlamp failure. My vehicle appears to exhibit the same condition even though my VIN is excluded from the recall population. I am requesting that NHTSA review whether the affected population for Recall 22V-261 may need to be expanded.
NHTSA complaint #11762288 — an unverified report by a vehicle owner.
Sacramento, CA
POWER TRAIN
The vehicle is experiencing an intermittent, sudden, and life-threatening drop into "limp home mode" while driving, creating an severe speed differential with surrounding traffic.First Incident (50,584 miles): The vehicle entered limp mode. Authorized Mercedes service center scanned the car, confirming Fault Code P019185 (Rail pressure sensor malfunction / signal above permissible limit value). The dealer applied an Engine Control Module software patch under Mercedes TSB LI07.70-P-078047.Second Incident (53,695 miles): Less than 3,000 miles later, the exact same sudden powertrain failure recurred. The vehicle drastically lost propulsion power immediately after exiting a high-speed freeway, leaving the driver in an incredibly vulnerable, unsafe position.The manufacturer's documented software remedy has completely failed to fix the underlying powertrain defect, leaving a known hardware component failure unaddressed while actively endangering vehicle occupants.
NHTSA complaint #11760688 — an unverified report by a vehicle owner.
Sacramento, CA
ENGINE
The vehicle is experiencing an intermittent, sudden, and life-threatening drop into "limp home mode" while driving, creating an severe speed differential with surrounding traffic.First Incident (50,584 miles): The vehicle entered limp mode. Authorized Mercedes service center scanned the car, confirming Fault Code P019185 (Rail pressure sensor malfunction / signal above permissible limit value). The dealer applied an Engine Control Module software patch under Mercedes TSB LI07.70-P-078047.Second Incident (53,695 miles): Less than 3,000 miles later, the exact same sudden powertrain failure recurred. The vehicle drastically lost propulsion power immediately after exiting a high-speed freeway, leaving the driver in an incredibly vulnerable, unsafe position.The manufacturer's documented software remedy has completely failed to fix the underlying powertrain defect, leaving a known hardware component failure unaddressed while actively endangering vehicle occupants.
NHTSA complaint #11760688 — an unverified report by a vehicle owner.
Sacramento, CA
FUEL/PROPULSION SYSTEM
The vehicle is experiencing an intermittent, sudden, and life-threatening drop into "limp home mode" while driving, creating an severe speed differential with surrounding traffic.First Incident (50,584 miles): The vehicle entered limp mode. Authorized Mercedes service center scanned the car, confirming Fault Code P019185 (Rail pressure sensor malfunction / signal above permissible limit value). The dealer applied an Engine Control Module software patch under Mercedes TSB LI07.70-P-078047.Second Incident (53,695 miles): Less than 3,000 miles later, the exact same sudden powertrain failure recurred. The vehicle drastically lost propulsion power immediately after exiting a high-speed freeway, leaving the driver in an incredibly vulnerable, unsafe position.The manufacturer's documented software remedy has completely failed to fix the underlying powertrain defect, leaving a known hardware component failure unaddressed while actively endangering vehicle occupants.
NHTSA complaint #11760688 — an unverified report by a vehicle owner.
Cherry Hill, NJFire
UNKNOWN OR OTHER
While the vehicle was being operated normally, it caught fire. We were driving on a summer day in August. Conditions were humid, with temperatures in the mid-80s. The vehicle was on the return leg of an approximately 30-mile drive. Traffic was somewhat heavy, with speeds generally below 20 mph and occasional stops. We first noticed a slight burning smell, followed shortly afterward by a distinct puff of white smoke coming from under the hood on the passenger side, near the windshield. We immediately decided to stop the vehicle and get out. Within approximately 30 seconds, we observed the first visible flames. Within about one minute, the fire had spread rapidly and the vehicle was engulfed in flames. By approximately 3½ minutes, the entire front half of the vehicle had been destroyed by the fire. Parts of the vehicle were blown off during the fire, with some debris traveling across the roadway and into the nearby woods. Fortunately, there were no injuries because we recognized the danger and exited the vehicle quickly.
NHTSA complaint #11760363 — an unverified report by a vehicle owner.
Trussville, AL
ENGINE
While driving in my neighborhood at 25 MPH, my Mercedes GLC300 suddenly lost power and the check engine light illuminated. My car would no longer exceed 25-30 MPH, but I drove it straight to the dealership and they said it was a faulty cylinder head and will cost $10,000 to fix! After intense negotiations, they agreed to fix it for $4,205.58, which was better, but still, that’s a lot to pay for a manufacturer’s defect! My car is a 2021 with only 67,540 miles on it.
NHTSA complaint #11739133 — an unverified report by a vehicle owner.
Pompton Plains, NJ
ENGINE
Getting P06DA trouble code meaning that there is something wrong with the oil pressure solenoid in the oil sump. this is a known issue where the wiring of the solenoid get frayed. cost of repair for the (cheap part) is $7,500 because of 18 hour labor involved. MB knows this is an issue with the wiring in the solenoid. I'm not sure if there is a fire risk because of the frayed wires.
NHTSA complaint #11735862 — an unverified report by a vehicle owner.
Oxnard, CA
POWER TRAIN
The engine starts shaking, smell of gas car than stops while driving, could caused an accident and severely injured someone on the freeway. This is a major safety issue after further researching this particular issue MB of Canada issue a warranty letter extension for this particular but nothing for US.
NHTSA complaint #11724468 — an unverified report by a vehicle owner.
Pittsburg, CA
EXTERIOR LIGHTING
Headlight is defective and is filled with condensation which has caused the entire light to fail. The problem has been confirmed by a independent service center. The light has not been inspected by a manufacturer however the manufacturer was contacted and denied that a recall exists however other purchasers have reported the same issue. There have been no apparent issues prior to this problem.
NHTSA complaint #11724095 — an unverified report by a vehicle owner.
at 96,000 milesPharr, TX
BACK OVER PREVENTION: SENSING SYSTEM: CAMERA
The contact owns a 2021 Mercedes-Benz GLC300. The contact stated that the rear-view camera was not functioning properly. After restarting the vehicle, the camera operated as needed; however, several days later, the camera became inoperable. The contact referenced NHTSA Campaign Number: 21V354000 (Back Over Prevention, Electrical System); however, the VIN was not included in the recall. The dealer was not notified of the failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 96,000.
NHTSA complaint #11724158 — an unverified report by a vehicle owner.
Nokomis, FL
ELECTRICAL SYSTEM
This is a well-known issue with these engines. See TSB (Service Bulletin) The 2021 Mercedes-Benz GLC 300 has 42,000 miles and the warranty ran out 2 weeks ago. The vehicle is up-to-date on service. Fault code P06DA00 Engine Oil Pressure Control Circuit/Open. The Yellow Check Engine Light came on and the engine does not run properly and causes engine damage. We had to drive it slowly, under 45 mph, to the nearest dealership. This is a safety issue. To replace the oil pump control valve solenoid and the wire harness for this feature is $5009.00 at Mercedes-Benz. The part cost is about $300 retail, and the rest is all labor fees.
NHTSA complaint #11718651 — an unverified report by a vehicle owner.
Nokomis, FL
ENGINE
This is a well-known issue with these engines. See TSB (Service Bulletin) The 2021 Mercedes-Benz GLC 300 has 42,000 miles and the warranty ran out 2 weeks ago. The vehicle is up-to-date on service. Fault code P06DA00 Engine Oil Pressure Control Circuit/Open. The Yellow Check Engine Light came on and the engine does not run properly and causes engine damage. We had to drive it slowly, under 45 mph, to the nearest dealership. This is a safety issue. To replace the oil pump control valve solenoid and the wire harness for this feature is $5009.00 at Mercedes-Benz. The part cost is about $300 retail, and the rest is all labor fees.
NHTSA complaint #11718651 — an unverified report by a vehicle owner.
at 41,000 milesSan Ramon, CA
EXTERIOR LIGHTING
The contact owns a 2021 Mercedes-Benz GLC300. The contact stated that the passenger’s side headlight was developing fog, causing the light to be dim. The vehicle was taken to the dealer, who diagnosed the vehicle and determined that the headlight needed to be replaced. The vehicle was not repaired. The contact learned of NHTSA Campaign Number: 22V261000 (Exterior Lighting); however, the VIN was not included. The manufacturer was informed of the failure and confirmed that the VIN was not included in the recall. The manufacturer referred the contact to the NHTSA Hotline to report the failure. The failure mileage was 41,000.
NHTSA complaint #11710686 — an unverified report by a vehicle owner.
Carlsbad, CA
POWER TRAIN
Vehicle Information: Year: 2021 Make: Mercedes-Benz Model: GLC 300 Engine: M264 Mileage at time of failure: Approximately 65,000 miles Complaint Description: While driving, my 2021 Mercedes-Benz GLC 300 began experiencing repeated engine misfires and rough running, accompanied by a persistent check engine light. These symptoms began shortly after I purchased the vehicle and progressively worsened over time. The vehicle exhibited reduced engine performance and hesitation while driving. The condition was intermittent at first but became more frequent, indicating a progressive mechanical issue rather than a sudden failure. At approximately 65,000 miles, the vehicle was evaluated by an authorized Mercedes-Benz dealership and diagnosed with a catastrophic cylinder head failure, requiring full cylinder head replacement. The estimated repair cost is approximately $8,000. The vehicle has never been modified and has not undergone prior engine repairs. The failure occurred well before what would be considered normal wear for an engine component of this type. Based on the progression of symptoms, the dealer diagnosis, and similar reports from other owners of the same model and engine, this appears to be a systemic defect involving the cylinder head and valve train, rather than an isolated incident or maintenance-related issue. This condition presents a potential safety concern due to loss of engine performance, drivability issues, and the risk of reduced power while operating the vehicle.
NHTSA complaint #11709709 — an unverified report by a vehicle owner.
Jersey City, NJ
ENGINE
Cylinder head valve seat leak ..vehicle Mia fires and check engine light on
NHTSA complaint #11709578 — an unverified report by a vehicle owner.
Carlsbad, CA
ENGINE
Vehicle Information: Year: 2021 Make: Mercedes-Benz Model: GLC 300 Engine: M264 Mileage at time of failure: Approximately 65,000 miles Complaint Description: While driving, my 2021 Mercedes-Benz GLC 300 began experiencing repeated engine misfires and rough running, accompanied by a persistent check engine light. These symptoms began shortly after I purchased the vehicle and progressively worsened over time. The vehicle exhibited reduced engine performance and hesitation while driving. The condition was intermittent at first but became more frequent, indicating a progressive mechanical issue rather than a sudden failure. At approximately 65,000 miles, the vehicle was evaluated by an authorized Mercedes-Benz dealership and diagnosed with a catastrophic cylinder head failure, requiring full cylinder head replacement. The estimated repair cost is approximately $8,000. The vehicle has never been modified and has not undergone prior engine repairs. The failure occurred well before what would be considered normal wear for an engine component of this type. Based on the progression of symptoms, the dealer diagnosis, and similar reports from other owners of the same model and engine, this appears to be a systemic defect involving the cylinder head and valve train, rather than an isolated incident or maintenance-related issue. This condition presents a potential safety concern due to loss of engine performance, drivability issues, and the risk of reduced power while operating the vehicle.
NHTSA complaint #11709709 — an unverified report by a vehicle owner.
Ocean Township, NJ
ENGINE
While I was driving on the Garden State Parkway, my vehicle experienced a sudden loss of power and persistent misfires and my check engine light came on. I was put in a position of a significant crash risk due to the fact that the vehicle loss sudden acceleration power while entering the parkway. I was almost rear ended by another vehicle. I drove immediately to a Mercedes-Benz dealer. The dealer confirmed a catastrophic cylinder head engine failure. The vehicle had only 39,000 miles. After some investigating, there have been numerous complaints from vehicle owners with the same issue on the M264 engine (which is what my vehicle has). I request that the NHTSA investigate the premature cylinder head engine failure. Not only was I put at risk for a possible significant accident, the manufacturer has refused to consider some reimbursement for my $10,000 repair. The vehicle was only 3,000 miles out of warranty at the time of the engine failure. A safety issue seems to be warranted and possibly a recall because of the many complaints on the GLC website. Please investigate.
NHTSA complaint #11707845 — an unverified report by a vehicle owner.
Marion, VA
ENGINE
There is a hesitation in or "shuddering" that causes the car to go into limp mode while in operation. I was in traffic and the car just powered down and would not get up to and or maintain speed. I contacted the local dealership and was told that there are other models and or engines in this car that have this issue and that they actually have a recall on this issue. The dealership noted that they have 1 or more that require this exact repair on every single week. The dealer told me what was wrong with it by the code it threw... He didn't have any hesitation because he is so familiar with this issue. The warning lights came on after the car powered decreased... there was no "pre" warning that this was going to happen.
NHTSA complaint #11698959 — an unverified report by a vehicle owner.
Vero Beach, FL
FUEL/PROPULSION SYSTEM
The vehicle lost power and will not operate over 40 mph/2000 rpms
NHTSA complaint #11697192 — an unverified report by a vehicle owner.
Hurst, TX
ENGINE
Twice my car slowed down tremendously in traffic because of a bad cylinder head. I drive a 2021 Mercedes GLC 300 4matic with 33,529 miles. In reviewing other complaints, this is a common and known complaint. My check engine light came on and I could not go over 40 mph. This is very dangerous.
NHTSA complaint #11696080 — an unverified report by a vehicle owner.
Scottsdale, AZ
ENGINE
Car has experienced rough idling, sluggish to no acceleration, check engine light illuminates and no shifting of gears regardless of speed. It appears to be going into limp mode. This has occurred monthly for the last four months. After pulling over, the car is turned off, wait five seconds and then turn it back on the car operates like nothing has happened. Here is when it has happened: 1.In a drive-thru lane to get some food 2.Waiting in a left-hand turn land 3.Driving through a parking lot at 10 mph 4.Driving on a road at 45 mph The date below is the last occurrence.
NHTSA complaint #11695359 — an unverified report by a vehicle owner.
Fredericksburg, VA
ENGINE
Check engine light came on. Code was P219D mixture formation is irregular on cylinder 2. Informed today, the cylinder will need to be replaced entirely for about $10,000. Concerned that although this did not happen to me, others have stated the vehicle completely stalls while driving.
NHTSA complaint #11688954 — an unverified report by a vehicle owner.