FaultScore report
Owners have filed 84 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.
FaultScore 51/100
Higher is worse. Measured against the other years of the Mercedes Benz GLC 300.
How this is worked out84
Complaints
1
Crashes reported
1
Fires reported
0
Injuries reported
19,369 mi
Median mileage at failure
Half of reported failures happened before this
73%
Failed under 36,000 miles
Inside a typical bumper-to-bumper warranty
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.
Click any bar to open that year's report.
Every complaint is filed against a part. Follow any row for the complaints about that part alone.
Median failure at 96,000 miles
0 crashes, 1 fires
Median failure at 25,000 miles
Median failure at 10 miles
Median failure at 7,000 miles
Odometer readings owners gave when they filed. About half of all complaints include one.
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.
Reports where the owner recorded a crash, a fire, an injury or a death.
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.
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.
In the owners' own words, exactly as filed with NHTSA.
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.
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.
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.
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.
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.
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.
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.
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.
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.
ENGINE
Cylinder head valve seat leak ..vehicle Mia fires and check engine light on
NHTSA complaint #11709578 — an unverified report by a vehicle owner.
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.
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.
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.
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.
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.
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.
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.
ENGINE
what happened? While driving, all of sudden, engine light was on and shaky with rough vibration consequently loss of power. I pulled over and turned off engine. Engine light disappeared after restarted. It happened again and had diagnostics at the dealership. Software update was given at first solution. However, next day, engine light on again, visited the dealership and it turned out there are leak on cylinder head. It seems a known issue. there are similar cases where vehicle could have been in critical situation. [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11683317 — an unverified report by a vehicle owner.
EXTERIOR LIGHTING
The headlights stopped working due to water entering the assembly unit. First one side went out and then eventually the other side went out. The car was brought in to the dealership to fix and they stated it wasn’t covered. I’m recently learning about a recall of this issue with my type of car and I’m being told that my vehicle is not included in the recall.
NHTSA complaint #11682064 — an unverified report by a vehicle owner.
EXTERIOR LIGHTING
Have been getting condensate inside vehicle headlights inwhich have cause the headlight to completely not work anymore.. There is no damage to headlight which means to be cause due to a problem with the seal. Checked with local and also statewide Mercedes advisors which was told there isn’t a recall for my vehicle inwhich I looked online and found an recall for vehicles just like the one I have.. Recall number 22V261000-Recall Date 04-14-2022. I’m asking for my vehicle to be inspected and repaired free of charge . Thanks and sorry for the bother - Can’t drive vehicle at night due to headlight malfunction and it’s very unsafe for me and kids and family
NHTSA complaint #11674539 — an unverified report by a vehicle owner.
ELECTRICAL SYSTEM
Have been getting condensate inside vehicle headlights inwhich have cause the headlight to completely not work anymore.. There is no damage to headlight which means to be cause due to a problem with the seal. Checked with local and also statewide Mercedes advisors which was told there isn’t a recall for my vehicle inwhich I looked online and found an recall for vehicles just like the one I have.. Recall number 22V261000-Recall Date 04-14-2022. I’m asking for my vehicle to be inspected and repaired free of charge . Thanks and sorry for the bother - Can’t drive vehicle at night due to headlight malfunction and it’s very unsafe for me and kids and family
NHTSA complaint #11674539 — an unverified report by a vehicle owner.
VISIBILITY/WIPER
Have been getting condensate inside vehicle headlights inwhich have cause the headlight to completely not work anymore.. There is no damage to headlight which means to be cause due to a problem with the seal. Checked with local and also statewide Mercedes advisors which was told there isn’t a recall for my vehicle inwhich I looked online and found an recall for vehicles just like the one I have.. Recall number 22V261000-Recall Date 04-14-2022. I’m asking for my vehicle to be inspected and repaired free of charge . Thanks and sorry for the bother - Can’t drive vehicle at night due to headlight malfunction and it’s very unsafe for me and kids and family
NHTSA complaint #11674539 — an unverified report by a vehicle owner.
ENGINE
Head problems
NHTSA complaint #11667209 — an unverified report by a vehicle owner.
ENGINE
In September 2024 my vehicle's engine light came off and the car was struggling to accelerate, especially in highway. I took it to Mercedes Benz of Cincinnati and they acknowledged the fault, made some repairs (under warranty) but the mechanic told us he had already seen quite a few of these cars needing the engine to be replaced. The problem keep coming back and took in in May 2025 (4 months after warranty expired) with the same exact issue. Now they said it is a cylinder head that needs replacement and that it will cost me $10K. This problem has now been reported by several drivers for this model car within less than 5 years of being made. In Canada, the same type of engine has seen same problem so Mercedes extended the warranty for 15 years on the cylinder heads. They need to do the same for the GLC engines and cover our repairs.
NHTSA complaint #11661749 — an unverified report by a vehicle owner.
ENGINE
Our 2021 Mercedes is 4 years old and had the engine light come on. The vehicle has always been maintenance by Mercedes and well taken care of. The engine had a Cylinder Head Failure which resulted in a $7600 repair for a 4 year old vehicle. Mercedes refused to offer a good will repair. This is A major issue reported in 2015–2016 M274 engine which can lead to catastrophic engine failure 1. These failures often result in loss of power, strange engine noises, and in severe cases, engine seizure. The damage can extend to the cylinder head, especially if broken piston fragments impact the combustion chamber. This is a major risk for all owners of 4 cylinder Mercedes. Mercedes of Canada has already issued an extended warranty but owners of US Mercedes vehicles are left on the hook for the bill and risking their lives while this is a known issue.
NHTSA complaint #11660968 — an unverified report by a vehicle owner.