2021 Mercedes-Benz GLC63 AMG S
The 2021 Mercedes-Benz GLC63 S AMG is a high-performance compact SUV that offers exhilarating performance and luxurious features. The GLC lineup also includes the standard GLC300 with a 2.0L turbocharged inline-4, and the GLC43 AMG with a more powerful V6. However, the GLC63 S boasts a handcrafted 4.0L twin-turbo V8 engine producing 503 horsepower and 516 lb-ft of torque. Owners rave about its ferocious acceleration, precise handling, and upscale interior. Criticisms often center on its firm ride, high price, and potentially costly maintenance. All GLC63 S models are equipped with a 9-speed automatic transmission.
Engine
4.0L Twin-Turbo V8
- Turbocharger Failure
- Description/Symptoms: Whining or screeching noises from the engine, reduced power, check engine light. Can be caused by oil starvation or mechanical failure of the turbocharger itself.
- Solution: Replacing the failed turbocharger(s).
- Estimated Cost to Fix: $3,000 - $6,000+ (depending on if one or both turbos need replacement and if performed at a dealership)
- Recalls: None Found
- Excessive Oil Consumption
- Description/Symptoms: Needing to add oil frequently between scheduled oil changes, blue smoke from the exhaust, oil leaks.
- Solution: Diagnosis to determine the root cause, which could include worn piston rings, valve stem seals, or turbocharger seals. Repair could involve replacing the affected components.
- Estimated Cost to Fix: $1,000 - $8,000+ (depending on the cause and extent of the repair)
- Recalls: None Found
- Spark Plug Issues
- Description/Symptoms: Misfires, rough idle, decreased fuel economy, check engine light.
- Solution: Replacing the spark plugs. Using OEM or recommended high-performance plugs is crucial.
- Estimated Cost to Fix: $300 - $600 (depending on the shop and type of spark plugs)
- Recalls: None Found
Transmission
9-Speed Automatic (AMG SPEEDSHIFT MCT 9G)
- Rough Shifting/Hesitation
- Description/Symptoms: Harsh or delayed shifts, particularly between certain gears. Hesitation when accelerating.
- Solution: Software update (TCU re-flash) to improve shift logic. In some cases, a transmission fluid flush and filter replacement may help. If the problem persists, valve body replacement or transmission rebuild might be necessary.
- Estimated Cost to Fix: $200 (software update) - $5,000+ (transmission rebuild)
- Recalls: None Found
- Transmission Fluid Leaks
- Description/Symptoms: Visible fluid leaks under the vehicle, difficulty shifting, transmission slipping.
- Solution: Replacing the leaking seals or gaskets. Common leak points include the transmission pan gasket, the valve body, and the transmission input shaft seal.
- Estimated Cost to Fix: $300 - $1,500+ (depending on the location and severity of the leak)
- Recalls: None Found
Suspension
- Air Suspension Malfunctions (if equipped)
- Description/Symptoms: Vehicle sagging on one or more corners, error messages related to the air suspension system, compressor not running, rough ride.
- Solution: Diagnosing the source of the leak or malfunction. This could involve replacing air struts, the air compressor, or associated sensors.
- Estimated Cost to Fix: $1,000 - $4,000+ per strut (depending on location and if performed at a dealership). Compressor replacement is typically $800 - $1,500.
- Recalls: None Found
- Squeaking Noises
- Description/Symptoms: Squeaking or creaking noises coming from the suspension when going over bumps or turning.
- Solution: Inspect and lubricate suspension components, such as ball joints, control arm bushings, and sway bar end links. If lubrication doesn’t resolve the issue, replacement of worn parts may be necessary.
- Estimated Cost to Fix: $100 - $500+ (depending on the parts needing replacement)
- Recalls: None Found
Electrical
- Infotainment System Freezing/Crashing
- Description/Symptoms: The MBUX infotainment system freezes, reboots unexpectedly, or displays error messages.
- Solution: Software update, resetting the system, or in severe cases, replacing the infotainment unit.
- Estimated Cost to Fix: $0 (software update) - $2,000+ (infotainment unit replacement)
- Recalls: None Found
- Sensor Malfunctions (Parking Sensors, Blind Spot Monitoring)
- Description/Symptoms: Inaccurate readings or complete failure of parking sensors, blind spot monitoring system not working, error messages on the dashboard.
- Solution: Diagnosing the faulty sensor and replacing it. Sometimes, recalibration of the system is required after sensor replacement.
- Estimated Cost to Fix: $200 - $800+ per sensor (depending on location and type)
- Recalls: None Found
- Battery Drain Issues
- Description/Symptoms: Car battery draining overnight or after short periods of inactivity.
- Solution: Identifying the parasitic draw. This could involve testing various circuits and components to pinpoint the source of the drain. Once identified, the faulty component needs to be repaired or replaced.
- Estimated Cost to Fix: $100 - $1,000+ (depending on the complexity of the issue)
- Recalls: None Found
Exterior
- Sunroof Issues
- Description/Symptoms: Sunroof not opening or closing properly, making excessive noise, leaking water.
- Solution: Inspecting and lubricating the sunroof tracks and mechanism. Replacing damaged or broken components, such as the motor or seals.
- Estimated Cost to Fix: $200 - $1,500+ (depending on the severity of the issue)
- Recalls: None Found
Interior
- Seat Motor Failures
- Description/Symptoms: Electric seats not moving in one or more directions.
- Solution: Replacing the faulty seat motor.
- Estimated Cost to Fix: $500 - $1,200+ per motor (depending on the location and if performed at a dealership)
- Recalls: None Found
- Trim Pieces Loosening/Rattling
- Description/Symptoms: Interior trim pieces, such as door panels or dashboard trim, becoming loose or rattling.
- Solution: Re-securing the trim pieces. This may involve replacing clips or fasteners.
- Estimated Cost to Fix: $50 - $300+ (depending on the complexity of the repair)
- Recalls: None Found
Summary
The 2021 Mercedes-Benz GLC63 S AMG is a powerful and luxurious vehicle but can be prone to issues associated with high-performance vehicles. The most significant potential problems revolve around the engine (specifically turbocharger and oil consumption issues) and transmission, which can lead to very expensive repairs. Electrical issues, particularly with the infotainment system, are also relatively common. While some issues are relatively minor, others can be quite costly to address. Potential buyers should have a pre-purchase inspection done by a mechanic familiar with AMG vehicles to identify any potential problems before buying.