2021 Mercedes-Benz GLC 300 engine problems
29 owner complaints filed with NHTSA name the engine on the 2021 Mercedes-Benz GLC 300 — 48% of all complaints for this model year.
What owners report
“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
“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…”
filed May 5, 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, 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 for all dealer returns is no later than…
PSL-NCU Return Parts 6/19 · Other · issued Jun 19, 2026
Engine problems in other GLC 300 years
| Year | Reports | Share |
|---|---|---|
| 2024 GLC 300 | 7 | 33% |
| 2023 GLC 300 | 15 | 27% |
| 2022 GLC 300 | 9 | 16% |
| 2020 GLC 300 | 20 | 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.