Used Mercedes-AMG C63 S review

Exterior Issues:

• Several owners have reported issues with the black plastic trim fading. Components such as the roof rails, door trim, and front intake surrounds can fade to a dark blue color over time. Additionally, this black trim can become loose and eventually start to rattle.
• Sunroof problems are also common, ranging from minor issues like squeaking or rattling to complete failures that can cost thousands to repair. Problems include rubber seals deteriorating, cables breaking, motors seizing, alignment issues, and electronic failures that prevent the sunroof from opening or closing properly. Some unfortunate owners have had their sunroofs fail to close just as it started to rain.
• Door seals often require attention due to issues with rattles, squeaks, and excessive wind noise. The badging on the front quarter panels, particularly the “T” in “bi-turbo,” can fall off. Carbon trim, especially on the mirror cowls, can flake, and small aero clips on the rear wheel arch can disappear in car washes. Cars with the extended front splitter are prone to damage when navigating driveways.
• Cleaning the C63 requires caution, as some cleaning products can turn the window trim into a rainbow hue, potentially costing thousands to replace. Incorrect cleaning products can also cause brake calipers to fade to a milky finish. Additionally, some owners have experienced electronic issues with power windows and mirrors malfunctioning.
• According to Mercedes dealership technicians, quality control varies greatly among individual cars. Some vehicles exhibit perfect panel gaps and no issues, while others return to the dealership repeatedly with various problems. Technicians also noted that cars from 2017 tend to have better fit and finish, but quality has diminished in later models, even according to AMG specialists.

Interior Issues:

• There are numerous reports of issues with the infotainment system, including Bluetooth and radio signals dropping out, screens locking up or displaying glitchy images, and the entire system restarting and losing saved presets. The native sat-nav system is notoriously unreliable, with some owners reporting that it incorrectly places the car in the middle of the Pacific Ocean.
• Dealership technicians note that earlier infotainment systems are generally more stable, while newer systems with more functionality tend to have more issues. Although software updates often resolve these problems, some owners have had to replace the entire system, typically under warranty, which will not last indefinitely.
• The headliner can come loose, similar to issues seen in older cars like the Ford Falcon. One owner was quoted $1500 for this repair, although anything over $500 is considered excessive.
• Optional performance seats (option code 555) can have squeaky chrome plastic trim, and fixing this issue can be challenging. Some owners have also experienced rattling speakers and noted that the sound quality in pre-update cars did not meet expectations, leading Mercedes to upgrade the amplifier in post-facelift models.
• The HVAC system can also present problems, from malfunctioning commands to the console becoming too hot to touch if the aircon temperature is set above 20 degrees. Reports include blower motor failures and heater core issues. Wagon owners have mentioned a reverberation or hum from the rear corners.
• Many owners report rattles, squeaks, and creaks in various parts of the car, including the dashboard, instrument panel, door panels, windows, center console, and infotainment display. Given the car’s high price when new, such issues are unacceptable.
• Furthermore, replacement parts can be extremely costly. One owner, a mechanic, had to replace an ABS module for $7000. Window switches can break, the silver interior trim can chip, and glossy carbon or piano black plastic scratches easily. Manufacturers should avoid high gloss finishes in high-traffic areas unless using more resilient materials.
• Wear and tear on the interior varies by car, but the satin finish on the center console holds up well. However, the leather on the steering wheel can wear prematurely. Owners are advised to hold the steering wheel correctly to avoid unnecessary wear and prevent looking unprofessional.
• Additionally, certain cleaning products and hand creams can damage the Alcantara on the steering wheel, turning it into a sticky mess if an oily moisturizer is used.

Mechanical Issues:

• Many of the expected mechanical problems in these cars are actually not as prevalent. The engine internals, such as timing chains and turbos, are generally reliable. However, the cooling system can be problematic, especially in hot climates where overheating is an issue during hard driving or track days. Modified cars are particularly prone to overheating. The electronic thermostat can fail, usually getting stuck open rather than closed, but accessing it requires removing much of the front end of the car.
• The charge cooler radiator is prone to damage and leaks, so it’s advisable to check the central reservoir periodically. Occasionally, air/oil separator issues can cause vacuum leaks and lean air-fuel ratio problems, or positive crankcase pressure leading to oil leaks. If valve covers leak, removing them is almost impossible without taking out the engine, which is a costly and time-consuming process.
• Ignition coils and injectors are common sources of misfires, often due to oil filling up the spark plug tubes from a leaking valve cover seal, which again necessitates engine removal. Engine mounts also fail and are expensive to replace, making it wise to change them when the engine is out for other repairs.
• The 7-speed transmission in early versions (up to 2018) is considered more reliable than the later 9-speed, which had software and valve body issues typically resolved under warranty. The electronic limited-slip differentials are weak and not serviceable, often requiring expensive replacements. Axles can break under hard driving, especially in tuned cars.
• Modifications are generally discouraged, as pushing these engines often leads to various failures. While they can produce significant power, the longevity of such modifications is questionable.