Short answer: The biggest problems with the 2021 Mercedes GLC 300 are engine problems, electrical system issues, and structure problems.
Engine problems are the most common while electrical system issues and structure problems aren’t as common.
Some of these problems have even resulted in recalls: Mercedes has issued nine for this vehicle, several of which involve the vehicle’s emergency call system.
The 2021 Mercedes GLC 300 is a compact high-end vehicle that aims to provide comfort and an enjoyable driving experience to its passengers.
While many succeed in that mission, some unfortunately fall short due to manufacturer defects. In this article, we summarize the most common complaints from owners of the 2021 Mercedes GLC 300 who have experienced those defects for themselves.
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Common 2021 Mercedes GLC 300 Problems
2021 Mercedes GLC 300 Engine Problems
Engine problems in the 2021 Mercedes GLC 300 were often noticeable, with drivers reporting shaking and sudden power loss while driving.
Shaking
- Severity: Moderate to high; Engine shaking can compromise ride quality, reveal underlying mechanical faults, and, depending on the cause, pose safety issues
- Manufacturer’s Response: No recall or TSB released for shaking in the 2021 Mercedes GLC 300.
- Fix: Dealer should perform a full diagnostic: engine mount inspection, vibration analysis, drivetrain balance, misfire/fuel‑system check; repair or replace any defective parts identified.
Loss of Engine Power
- Severity: High; sudden loss of power while driving can lead to dangerous situations such as inability to accelerate or maintain speed, possibly causing accidents.
- Manufacturer’s Response: Mercedes issued a recall in June 2023 for fuel pump issues that could result in a loss of engine power, NHTSA Recall 23V-445.
- Fix: Dealers will replace the fuel pump free of charge.
2021 Mercedes GLC 300 Electrical System Issues
Drivers of the 2021 GLC 300 reported electrical issues like headlights going out due to moisture buildup inside the housing.
Headlights Going Out After Moisture Accumulation
- Severity: Moderate to high; headlight failure in wet or humid conditions reduces visibility.
- Manufacturer’s Response: Recall 22V261 covers certain 2021‑year GLC 300 vehicles where headlamp connector sealing plugs may not be watertight, allowing moisture ingress and potential headlight failure.
- Fix: Mechanics will inspect and replace the headlight sealing plugs as necessary free of charge.
2021 Mercedes GLC 300 Structure Problems
Structural issues in the 2021 GLC 300 included sudden sunroof explosions and poor headlight sealing that led to moisture buildup.
Spontaneous Sunroof Explosion
- Severity: High; a sunroof failure can create shards or structural failure, risking occupant injury.
- Manufacturer’s Response: No recall or TSB released for spontaneous sunroof explosion issues in the 2021 Mercedes GLC 300.
- Fix: Dealer should perform inspection of the sunroof assembly, glass condition, seals and mounting hardware. Replacement or reinforcement may be necessary.
Mercedes Benz GLC 300 Owner Complaints
“Twice my car slowed down tremendously in traffic because of a bad cylinder head. I drive a 2021 Mercedes GLC 300 4matic with 33,529 miles. In reviewing other complaints, this is a common and known complaint. My check engine light came on and I could not go over 40 mph. This is very dangerous.”
“The headlights stopped working due to water entering the assembly unit. First one side went out and then eventually the other side went out. The car was brought in to the dealership to fix and they stated it wasn’t covered. I’m recently learning about a recall of this issue with my type of car and I’m being told that my vehicle is not included in the recall.”
“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.”
Understanding the Lemon Law Process for Lemon Cars
The lemon law process typically begins when a vehicle develops a defect that continues to appear despite multiple repair attempts.
Once it becomes clear that the issue isn’t being resolved, the owner should start gathering all repair documents.
These records help demonstrate that the manufacturer or dealership had ample opportunity to fix the problem but failed to do so.
After collecting the paperwork, the next step is to consult with a lemon law attorney who can review the repair history and determine whether the vehicle meets the legal requirements.
Lemon Law remedies can include a vehicle replacement, buyback, or cash compensation. Because most lemon laws require the manufacturer to pay the consumer’s attorney fees if the case succeeds, owners usually do not have to pay upfront for legal help.
Ultimately, the lemon law process provides a clear path for consumers to obtain fair compensation when their vehicle cannot be made reliable.
| Affected Vehicle | Average Lemon Law Settlement |
| 2021 Mercedes Benz GLC 300 | $81,695 |
*Please note, the figures presented in the chart are approximations based on past case results and should not be interpreted as a prediction or guarantee. Each case is unique and requires personalized legal guidance.
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