What are the most common Mercedes-Benz SLC problems?
According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2017-2020 Mercedes-Benz SLC has 5 documented issues. The most frequently reported are: Rear Subframe Corrosion and Cracking, Crankcase Ventilation / PCV Valve Failure, Panoramic/Varo Roof Hydraulic or Latch Malfunction. Of these, 1 is rated critical and should be addressed promptly.
Is the Mercedes-Benz SLC reliable?
The 2017-2020 Mercedes-Benz SLC has 5 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 1 issue is rated critical: Rear Subframe Corrosion and Cracking. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
How much does it cost to fix common Mercedes-Benz SLC problems?
Repair costs for known Mercedes-Benz SLC issues range from $250 to $5,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Rear Subframe Corrosion and Cracking, typically costs $2,500-$5,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What year Mercedes-Benz SLC is the most reliable?
Reliability varies across model years of the Mercedes-Benz SLC. Based on documented issues, problems are most commonly reported in earlier model years. Au7o recommends checking the specific known issues for your target year before purchasing, and having a pre-purchase inspection performed by a qualified mechanic. Our known issues database covers the 2017-2020 Mercedes-Benz SLC with 5 documented issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports.
What is the 2017-2020 Mercedes-Benz SLC Rear Subframe Corrosion and Cracking?
Owners and Mercedes forums have repeatedly reported severe rust on the rear axle carrier/subframe on R172-platform cars, including late SLC models. Corrosion can progress from surface rust to perforation and cracking around suspension mounting points, especially in road-salt clim… Repairs typically run $2,500-$5,500. Severity: high.
What is the 2017-2020 Mercedes-Benz SLC Crankcase Ventilation / PCV Valve Failure?
Turbocharged 2.0L M274 engines used in the SLC 300 are known for crankcase ventilation diaphragm and PCV-related failures. When the valve assembly fails, it can create excessive vacuum or pressure in the crankcase, leading to rough idle, oil seepage, whistling noises, and lean-mi… Repairs typically run $350-$1,100. Severity: medium.
What is the 2017-2020 Mercedes-Benz SLC Panoramic/Varo Roof Hydraulic or Latch Malfunction?
The retractable hardtop system on the SLC is a known trouble area, with owner reports of roof operation stopping mid-cycle, latch faults, and hydraulic leaks. Common causes include leaking hydraulic cylinders, weak pump output, failed microswitches, or trunk partition/latch senso… Repairs typically run $300-$4,000. Severity: medium.
What is the 2017-2020 Mercedes-Benz SLC Battery Voltage and Electronic Module Faults?
SLC models are sensitive to battery condition, and weak main or auxiliary battery voltage can trigger multiple warning messages, start-stop malfunctions, and erratic electronic behavior. Owners frequently report random faults affecting windows, roof operation, lighting, and drive… Repairs typically run $250-$900. Severity: medium.
What is the 2017-2020 Mercedes-Benz SLC Thermostat / Coolant Pump Housing Leaks?
The M274 engine family has recurring reports of coolant leaks from the thermostat housing, water pump area, or plastic coolant fittings. Heat cycling can warp plastic housings or degrade seals, causing slow coolant loss that may eventually trigger overheating or coolant warnings. Repairs typically run $500-$1,400. Severity: medium.
