2021 Mercedes-Benz GLC 300 Engine Problems
- Complaints
- 30about this part
- Share
- 45%of 67 total for the year
- Median mileage
- 7,000miles
- Trend
- RisingComplaints filed in the last 3 full calendar years are at least 25% higher than in the 3 years before.
NHTSA recorded 30 complaints about the engine of the 2021 Mercedes-Benz GLC 300, 45% of the 67 complaints for this model year. Where a mileage was given, the median is 7,000 miles. 1 of these say a crash was involved, according to the filers.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“I have purchased the 2021 Mercedes-Benz glc 300 4matic coupe and noticed a design flaw on the car. As you can see in the attached picture, the front bumper provides no protection to the radiator. It has already started chipping due to the rock damage. This can leave the car impaired on the freeway which can be dangerous. I did contact the dealer and they said there is nothing they can do.”
NHTSA complaint #11399796, filed 2021-03, 10 miles“On april 21, 2021 at about 1800 (time), less than 45-hours after purchase of the new 2021 glc 300 vehicle, the internal combustion (engine) misfired and abruptly malfunctioned while in steady acceleration at 65-MPH. My family and I were headed eastbound on the ca-60 freeway in lane three (leftmost, fastest lane). As soon as the engine spontaneously sputtered, it abruptly stopped and intensely shook the entire car vigorously, aggressively, and continuously with no ability for control nor for the option to continue to accelerate. …”
NHTSA complaint #11413885, filed 2021-04, 90 miles“2021 mercedes glc. Consumer writes in regards to valve spring failure and stalled engine. The consumer stated shortly after purchasing the vehicle, the valve spring broke causing the engine to fail while driving. The failure mileage was 199. The consumer stated the roadside assistance grossly under estimated it's arrival time. Also, the consumer was in an unfamiliar area but, roadside assistance required an address before sending the tow truck. The consumer had to walk the street to find an address on a home. The consumer felt the dealership attempted to downplay the failure as a simple fix. …”
NHTSA complaint #11404535, filed 2021-03, 199 miles“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, filed 2025-10“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, filed 2026-05Related service bulletins
- 11035238Jul 24, 2026Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz, has determined that on certain MY 2019-2021 C-Class, G-Class, GLC, GT, S-Class (205, 463, 253, 190 & 222 platforms)…
- 11034064Jun 19, 2026Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline…
- 11030302Mar 27, 2026Complaint -Check engine light illuminated. -Engine runs rough. -Poor shifting or jerking when accelerating. -Fault codes stored related to mixture formation, injector quantity…
- 11028267Feb 2, 2026Complaint -Check engine light illuminated. -Engine runs rough. -Poor shifting or jerking when accelerating. -Fault codes stored related to mixture formation, injector quantity…
- 11028003Jan 23, 2026Dear Mercedes-Benz Owner: In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA…
- 11027580Jan 10, 2026In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA, LLC is extending the…
- 11008712Oct 4, 2024Complaint Check engine light on. One of the below fault codes is current in the engine control module (N3/10). P04DB29, P04DB31, P04DB79 Cause Open circuit or high resistance to…
- 11008056Sep 16, 2024Complaint Check engine light on. Fault code P207273 - "Throttle actuator valve is blocked due to ice" stored. Engine may crank and not start. Fault code P210185 may also be…
- 11005314Jul 20, 2024Complaint Yellow Coolant warning comes on in cluster Fault codes below are current or stored in MED41 P0A0500- The actuation of the circulation pump for the low-temperature…
- 11005313Jul 17, 2024Complaint Check engine light on and fault code P019185 current or stored in MED41 control unit. Adaptation and misfire faults may also be stored. Vehicle may enter limp home…
Engine: other model years
| Year | Complaints | Share of year |
|---|---|---|
| 2025 | 3 | 19% |
| 2024 | 7 | 33% |
| 2023 | 15 | 27% |
| 2022 | 10 | 16% |
| 2021 | 30 | 45% |
| 2020 | 22 | 31% |
| 2019 | 11 | 23% |
| 2018 | 28 | 32% |
| 2017 | 37 | 37% |
| 2016 | 38 | 29% |
Other parts of the 2021 Mercedes-Benz GLC 300
13 complaintsFuel system
12 complaintsElectrical system
8 complaintsOther or unknown
7 complaintsTransmission and drivetrain
4 complaintsVisibility (wipers, defrost, mirrors)
4 complaintsBack-over prevention (rear camera)
3 complaintsForward collision avoidance
3 complaintsBody and structure
3 complaintsLane departure
2 complaintsVehicle speed control
2 complaintsAir bags
1 complaints
← All problems reported for the 2021 Mercedes-Benz GLC 300
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 29, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology