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Other or unknownPart report

2021 Mercedes-Benz GLC 300 Other or unknown Problems

Complaints
7about this part
Share
10%of 67 total for the year
Median mileage
—not reported
Trend
Not enough dataFewer than 15 complaints, too few for a reliable trend.

NHTSA recorded 7 complaints about the other or unknown of the 2021 Mercedes-Benz GLC 300, 10% of the 67 complaints for this model year. 2 a fire, according to the filers.

Fewer than 15 complaints name this part, so treat the figures as a rough indication only.

Example complaints

Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.

“My sunroof exploded while I was driving on the highway. There were no other cars around me and no overpasses. There is no explanation for the sunroof breaking. I thought someone shot out my window. It was the scariest experience I have ever had driving. If there were cars around, it might have caused a major accident.”

NHTSA complaint #11502302, filed 2023-01

“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, filed 2024-12

“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. …”

NHTSA complaint #11760363, filed 2026-08

“While slowly backing out of the driveway and without contacting anything at all, the rear window completely shattered. The window has never been hit by anything and had no defects yet it completely shattered so clearly reflects a manufacturing defect of some sort that is incredibly dangerous to passengers or other vehicles, since it happens without warning and without the necessity of an impact of any kind.”

NHTSA complaint #11641925, filed 2025-02

Related service bulletins

Other or unknown: other model years

YearComplaintsShare of year
2025319%
2024314%
2023916%
2022711%
2021710%
20201521%
20191532%
20182023%
20171313%
20162116%

Other parts of the 2021 Mercedes-Benz GLC 300

Engine
30 complaints
Exterior lighting
13 complaints
Fuel system
12 complaints
Electrical system
8 complaints
Transmission and drivetrain
4 complaints
Visibility (wipers, defrost, mirrors)
4 complaints
Back-over prevention (rear camera)
3 complaints
Forward collision avoidance
3 complaints
Body and structure
3 complaints
Lane departure
2 complaints
Vehicle speed control
2 complaints
Air 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 31, 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