The 2021 Mercedes-Benz C63 AMG, the high-performance variant of the W205 C Class, has been revered for its brutal power, aggressive styling, and precision engineering. While it delivers exhilarating performance, does it hold up in terms of reliability?
In this deep dive, we examine real-world reliability ratings, common issues, maintenance costs, and ownership insights from J.D. Power and NHTSA. Whether you’re considering a used C63 AMG or already own one, this guide will provide an authoritative analysis of its long-term dependability.
Reliability Scores from Credible Sources
| Source | Reliability Score | Category |
|---|---|---|
| J.D. Power | 79/100 | “Average” |
| Consumer Reports | 2/5* | “Below Average” |
| NHTSA Recalls | Multiple Recalls Reported | “Moderate Concerns” |
J.D. Power: 71/100 Reliability Rating
J.D. Power assigns the C63 AMG an average reliability rating of 79/100. The model excels in engine durability and driving dynamics but struggles with electrical issues and expensive repairs.
Consumer Reports: 3/5 Rating
Consumer Reports doesn’t provide reliability records for the 2021 C63 AMG; instead, they rate the regular C-Class, which received a below-average score of 2 out of 5. While its powertrain is robust, long-term data have noted issues with infotainment malfunctions and oil leaks.
NHTSA Recalls and Safety Concerns
The National Highway Traffic Safety Administration (NHTSA) lists multiple recalls for the 2021 C63 AMG, These are as follows:
- Loss of Drive Power from Fuel Pump Shutdown (June 2023)
- Disabled Emergency Call System (May 2022)
- Inoperable Rearview Camera Display/FMVSS 111 (April 2022)
- Improperly Mounted Rear Headrests (May 2021)
- Faulty Front Seat Position Switch (April 2021)
As a niche sports car with fewer sales than mainstream models, the C63 isn’t always directly crash-tested by safety institutions. However, because it shares its platform with the regular C-Class—which earned a Top Safety Pick+ from the Insurance Institute for Highway Safety (IIHS)—the C63 is considered safe enough for everyday driving.
Common Issues with the Mercedes-Benz C63 AMG
Despite its legendary performance, the C63 AMG has several known reliability issues. Here’s what owners and mechanics commonly report:
1. Engine Oil Leaks & Head Bolt Failures
- The M156 6.2L V8 (2008–2015) and M177 4.0L Biturbo V8 (2015–present) both exhibit oil leaks at high mileage.
- Early M156 models suffer from weak head bolts, leading to catastrophic engine failure if untreated.
2. Transmission Problems
- Some 7G-Tronic and 9G-Tronic transmissions experience harsh shifts and occasional slipping.
- Torque converter failure is common in higher mileage units.
3. Suspension and Differential Issues
- AMG Ride Control adaptive dampers may fail, leading to expensive replacement costs.
- Limited-slip differentials in performance packages can develop clunking sounds or leaks over time.
4. Electrical System Malfunctions
- Infotainment system COMAND freezes or requires software updates.
- Faulty O2 sensors and fuel injector failures can trigger check engine lights.
5. Carbon Buildup in Turbocharged Models
- M177 twin-turbo V8 engines (2015–present) can suffer from intake valve carbon buildup, reducing performance and requiring walnut blasting.
Maintenance and Ownership Costs
The C63 AMG requires premium upkeep, given its high-performance nature. Below is an estimated breakdown of routine service costs:
| Service Type | Estimated Cost | Frequency |
| Oil Change | $150–$250 | Every 5,000–7,500 miles |
| Brake Pad Replacement | $500–$1,000 | Every 30,000 miles |
| Transmission Service | $500–$800 | Every 60,000 miles |
| Carbon Cleaning | $800–$1,500 | Every 40,000 miles |
| Differential Service | $400–$700 | Every 50,000 miles |
Is the Mercedes-Benz C63 AMG Worth Buying?
Pros
- Thrilling Performance – One of the best-sounding and most powerful AMG models.
- Luxury & Comfort – Premium materials, high-quality craftsmanship.
- Strong Engine Longevity – If well maintained, the M156 & M177 engines are highly durable.
- Resale Value – AMG models hold value better than standard C-Class variants.
Cons
- Expensive Maintenance – Higher upkeep costs than non-AMG Mercedes models.
- Potential Head Bolt Issues – Early M156 models need upgraded head bolts.
- Transmission Concerns – Some 9G-Tronic units require software tuning.
Final Verdict
The Mercedes-Benz C63 AMG is a thrilling but high-maintenance vehicle. It rewards enthusiasts with brutal power, luxury, and a legendary exhaust note, but owning one requires serious commitment to maintenance.
For prospective buyers, a well-documented service history is essential. Avoid neglected examples and ensure pre-purchase inspections (PPI) for potential carbon buildup, oil leaks, and transmission wear.
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