2020 Mercedes-benz GLC-Class Complaints

Water condensation within the driver side headlight which caused the complete headlight unit, control unit, and module to fail. This is a huge safety issue due to unable to operate vehicle safely during the when it comes to making left turns due to no signal indicator and a safety issue/hazard when driving at night. The issue has been inspected with a local dealer and with corporate being aware of the manufacturer defect. There were no indicators nor warning lamps prior to this issue.

The front main light on the driver side stopped working after a rain and it continued getting moister in the head lamp every night until a few days ago and as a result the head light assembly does not work at all ,the same thing is happening on the passenger side front head light assembly except it is still working .research showed that this has been a problem on similar Mercedes Benz cars and considering that the car has not had any accidents to possibly causing this it was concluded that this should have been part of the recalls .car is not operatable and i reached out to Mercedes Benz and they acted like I am out of my mind and it is passed the express warranties with car having 69000 miles. I tried explaining to them about the implied warranty and the safety problem and they continued with the same none sense. at this point The MBZ dealers want over $ 6000.00 to replace the part and I am not able to operate car.what can you do for me and others effected.

The engine in my 2020 Mercedes-Benz GLC 300 suddenly malfunctioned while driving on two separate occasions. The vehicle began shaking violently and lost power without warning. I could not accelerate and had to pull over immediately. I turned the vehicle off and restarted it to regain limited driveability. On the second incident, the power loss was so abrupt that it felt as if I had been rear-ended. I feared the vehicle would stall in traffic and cause a crash. Following these events, the check engine light remains constantly on. The dealer inspected the vehicle and confirmed excessive valve leakage into the exhaust system, requiring a complete cylinder-head replacement. They warned the failure will worsen and could result in sudden power loss again. This defect poses a serious safety risk. If the power loss occurs while merging or at highway speeds, it could easily lead to a rear-end collision. The vehicle has relatively low mileage for such a severe internal engine failure, and I ha...

My 2020 Mercedes-Benz GLC 300 experienced a complete engine failure at ~51,000 miles, shortly after a major repair for a known defect. Initially, the vehicle showed a misfire on cylinder #3, which was diagnosed at RBM of Alpharetta as low compression due to valve seat damage, matching MB TSB LI01.30-P-072328. The cylinder head was replaced in Aug 2025. About two months later, while driving under normal conditions, the vehicle made a loud cranking/knocking noise and completely stalled in traffic without any check engine light or warning. This sudden stall posed a serious safety risk. The vehicle was towed to the same dealer, who has now diagnosed the engine as fully seized and recommended a complete engine replacement. I had also completed the 50,000-mile scheduled service at the same dealer shortly before this failure. Despite this being clearly linked to a known design defect, Mercedes-Benz USA has declined to provide further assistance or goodwill coverage. I am reporting this to h...

Nationwide known cylinder head issues. Cylinder head work needing replaced.