2021 Mercedes-Benz GLC 300 problems and owner complaints
Explore the records behind recurring owner reports.
Key facts
64 owner complaints analyzed
9 distinct recall campaigns
26,500 mi median reported failure mileage
Scope: 2021 model year. Data snapshot: . 12 complaints include usable failure mileage.
Most common problems
Engine is the most frequently named component, appearing in 30 of 64 complaints (46.9%). A complaint can name multiple components.
| Topic | Matching reports | Share of complaints |
|---|---|---|
| Engine operation | 8 | 12.5% |
| Electrical and battery issues | 5 | 7.8% |
| Fuel system concerns | 3 | 4.7% |
| Braking behavior | 2 | 3.1% |
| Transmission and shifting | 1 | 1.6% |
Topic matches use published keyword rules. They describe mentions, including negations or comparisons, and do not confirm a diagnosis. Read the matching rules.
Component breakdown
Number of unique complaints naming each component. Top eight shown.
| Category | Count |
|---|---|
| Engine | 30 |
| Exterior Lighting | 11 |
| Fuel/Propulsion System | 10 |
| Electrical System | 8 |
| Unknown Or Other | 7 |
| Power Train | 4 |
| Structure:Body | 3 |
| Visibility/Wiper | 3 |
Engine: 30; Exterior Lighting: 11; Fuel/Propulsion System: 10; Electrical System: 8; Unknown Or Other: 7; Power Train: 4; Structure:Body: 3; Visibility/Wiper: 3
Reported problems by failure mileage
Complaint counts in mileage bands. These are not failure rates per vehicle or mile.
| Category | Count |
|---|---|
| Under 25,000 | 5 |
| 25,000 to 49,999 | 4 |
| 50,000 to 74,999 | 1 |
| 75,000 to 99,999 | 2 |
| 100,000 to 149,999 | 0 |
| 150,000 and above | 0 |
Under 25,000: 5; 25,000 to 49,999: 4; 50,000 to 74,999: 1; 75,000 to 99,999: 2; 100,000 to 149,999: 0; 150,000 and above: 0
Under 25,000 miles has the most reports with usable mileage (5). 52 complaints have missing, zero or invalid mileage.
Complaints over time
Year the complaint was filed, not the vehicle model year or incident year. The snapshot year is partial.
| Category | Count |
|---|---|
| 2021 | 11 |
| 2022 | 6 |
| 2023 | 4 |
| 2024 | 13 |
| 2025 | 18 |
| 2026 | 12 |
2021: 11; 2022: 6; 2023: 4; 2024: 13; 2025: 18; 2026: 12
Pattern summary
Engine leads the component reports. Engine operation appears in 8 complaint narratives. Electrical and battery issues appears in 5 complaint narratives. Fuel system concerns appears in 3 complaint narratives. Use these patterns to inspect individual reports and prepare questions for a mechanic.
Calculated from recorded counts. An AI narrative has not been published for this selection.
Complaint evidence
Examples provide context, not a representative sample or a verified diagnosis.
Owner report 11404535 · 2021-03-29 (March 29, 2021)
2021 MERCEDES GLC. CONSUMER WRITES IN REGARDS TO VALVE SPRING FAILURE AND STALLED ENGINE. *LD 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 DEALE…
Owner-reported narrative. 199 miles reported. Look up ODI 11404535 at NHTSA ↗
Owner report 11486730 · 2022-09-27 (September 27, 2022)
My car was bought new in October 2021 & I began having problems after having it for 6 months & the mileage at that time was about 4000 miles - it was in April 2022 & the check engine light came on & I had a loss of power to where it slowed down & would not go any faster than about 30/35 miles an hour going on a straight road way & no faster than about 10 miles an hour going uphill. The engine sounded funny as well. It had to be towed to the dealership for repair. This incident happened again a month later & it was towed to the dealership at th…
Owner-reported narrative. Look up ODI 11486730 at NHTSA ↗
Owner report 11441952 · 2021-11-29 (November 29, 2021)
The contact owns a 2021 Mercedes-Benz GLC300. The contact received a recall notification for NHTSA Campaign number: 21V354000 (Back Over Prevention, Electrical System). The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was notified of the issue. The part was not available for the repair. The contact had not experienced a failure. Parts distribution disconnect.
Owner-reported narrative. Look up ODI 11441952 at NHTSA ↗
Owner report 11632268 · 2024-12-24 (December 24, 2024)
Mercedes App displays low battery alert. Brought to dealer who stated Mercedes told them (dealer) to inform anyone coming in with this issue to just disregard the alert in the app. Had the battery checked anyway. At the conclusion was told I had to “drive the car longer so the battery would recharge”.
Owner-reported narrative. Look up ODI 11632268 at NHTSA ↗
Owner report 11618196 · 2024-10-04 (October 4, 2024)
Vehicle has a known engine failure. Leaking valve in Cylinder head. Cylinder 3 injector is faulty
Owner-reported narrative. Look up ODI 11618196 at NHTSA ↗
Owner report 11628817 · 2024-12-04 (December 4, 2024)
The contact owns a 2021 Mercedes-Benz GLC300. The contact stated that while driving at low speeds, the vehicle lost motive power struggling to produce enough power to propel itself on a slight incline. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the fuel pump. The vehicle was not repaired. The vehicle was then towed to the dealer, who confirmed the diagnosis. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA c…
Owner-reported narrative. Look up ODI 11628817 at NHTSA ↗
Owner report 11458518 · 2022-03-27 (March 27, 2022)
Unexpected Severe braking when changing into turn lane. Unexpected severe braking when approaching intersection with no cars in intersection or on either side of car.
Owner-reported narrative. Look up ODI 11458518 at NHTSA ↗
Owner report 11499353 · 2022-12-29 (December 29, 2022)
Vehicle will flash warnings on dash the the blind spot assist in inoperative and the front passenger air bag malfunction. The active brake assist is also malfunctioning as the two white cars colliding is on. The dealership as tried to fix this issue 5 times and has tried argue the the active brake assist is functioning normal.
Owner-reported narrative. Look up ODI 11499353 at NHTSA ↗
Owner report 11695359 · 2025-10-24 (October 24, 2025)
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 dat…
Owner-reported narrative. Look up ODI 11695359 at NHTSA ↗