2021 Mercedes-Benz GLC 300 engine problems
30 owner complaints filed with NHTSA name the engine on the 2021 Mercedes-Benz GLC 300 — 45% of all complaints for this model year.
What owners report
“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…”
filed Aug 30, 2026
“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…”
filed May 20, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Related service bulletins
Mercedes-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) vehicles, the engine control unit…
Emissions - 2024100016 · Emissions · issued Jul 24, 2026
Engine problems in other GLC 300 years
| Year | Reports | Share |
|---|---|---|
| 2024 GLC 300 | 7 | 33% |
| 2023 GLC 300 | 15 | 27% |
| 2022 GLC 300 | 10 | 17% |
| 2020 GLC 300 | 21 | 30% |
| 2019 GLC 300 | 11 | 24% |
| 2018 GLC 300 | 28 | 32% |
Other reported problem areas on the 2021 Mercedes-Benz GLC 300
Counts are unique NHTSA complaints naming this component group. Complaints are unverified owner reports; mileage is computed only from complaints that included a usable odometer reading.