2017 Mercedes-benz Slc-class
The Verdict
The 2017 Mercedes-benz Slc-class has 4 owner complaints filed with NHTSA. The most reported issues are body (2 complaints) and electrical (1 complaints). With a Klunk Score of 99/100, it earns a "Smooth Ride" rating. If you're shopping for a Mercedes-benz Slc-class, consider the 2018 model year which has 75% fewer complaints.
Safe Bet
The 2018 has 75% fewer complaints
View the 2018 Mercedes-benz Slc-class dashboard →
Klunk Score: Smooth Ride
This vehicle year has significantly fewer complaints than average. A reliable choice.
How is this calculated?
The Klunk Score ranks this vehicle year against all others in our database based on total owner complaints filed with NHTSA. 100 = fewest complaints (top tier), 0 = most complained-about. Scores above 60 are better than average; below 40 means more problems than most.
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Under the Hood
Each number is a complaint. Darker = bigger problem.
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Worst Problems
Complaints
The contact owns a 2017 Mercedes-Benz SLC300. The contact stated that while driving at an undisclosed speed, there was a loud whistling sound coming from the upper panel of the roof. The vehicle was taken to an independent mechanic, where it was diagnosed and determined that the bonding of the upper roof panel had failed and required to be replaced. The vehicle was not repaired, and the contact was referred to the dealer for additional assistance. The dealer was contacted; however, the vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA Hotline for further assistance. The failure mileage was not available.
On September 6, 2025 while driving approximately 70 mph, the front roof panel of my vehicle detached completely. This was not only a costly failure, but also an extremely dangerous incident that could easily have caused severe injuries or fatalities — either to myself, my passengers, or other motorists on the roadway. As you are aware, Mercedes-Benz has already acknowledged this precise risk through NHTSA Recall No. 21V197000 / Campaign 2021070010, later expanded under NHTSA Recall 23V854000. These documents confirm that the bonding adhesive used on the front roof panel can deteriorate, leading to detachment. Mercedes has therefore had prior knowledge of this defect and its associated safety hazards. Given that my vehicle has now experienced the exact failure described in these recalls, it is wholly unreasonable for Mercedes-Benz to deny responsibility. This was not normal wear and tear; it was a known, documented safety defect that could have resulted in catastrophic consequences.
Piston 1 broken at 76000 miles. Compleat engine failer
TL* THE CONTACT OWNS A 2017 MERCEDES-BENZ SLC300. THE CONTACT RECEIVED NOTIFICATION OF NHTSA CAMPAIGN NUMBER: 21V058000 (COMMUNICATION, ELECTRICAL SYSTEM) HOWEVER, THE PART TO DO THE RECALL REPAIR WAS NOT YET AVAILABLE. THE VEHICLE WAS TAKEN TO MERCEDES-BENZ OF HILTON HEAD (155 FORDING ISLAND RD, BLUFFTON, SC 29910) WHERE THE CONTACT WAS INFORMED THAT THE UPDATE WAS NOT YET AVAILABLE. THE MANUFACTURER WAS MADE AWARE OF THE ISSUE AND CONFIRMED THE INFORMATION PROVIDED BY THE DEALER. THE CONTACT HAD NOT EXPERIENCED A FAILURE. PARTS DISTRIBUTION DISCONNECT.