The Mercedes-Benz A-Class W177 A 45 S AMG represents the pinnacle of performance and luxury in the compact car segment. With its aggressive styling, cutting-edge technology, and a hand-built AMG engine, it’s a dream car for enthusiasts. However, even a high-performance vehicle like the A 45 S AMG has challenges. In this detailed guide, we will explore the common problems reported by owners, their causes, and potential solutions, offering a comprehensive resource for prospective buyers and current owners alike.
Mercedes-Benz A-Class W177 A 45 S AMG Engine Performance Challenges
The centrepiece of the A 45 S AMG is its turbocharged 2.0-litre four-cylinder engine, one of the most powerful engines of its kind. While it delivers exhilarating performance, it has also been associated with specific issues.
Turbocharger Stress and Wear
The A 45 S AMG turbocharger is critical for its impressive power output. However, it is also one of the most stressed components in the vehicle. Over time, turbochargers can develop wear due to extreme temperatures and high pressures. Symptoms of a failing turbocharger include a loss of power, increased exhaust smoke, and a noticeable whistling noise under acceleration. Regular oil changes and proper warm-up and cool-down procedures can help extend the turbo’s lifespan, while more severe cases may require a replacement.
Oil Leaks and Consumption
Oil consumption and leaks are common complaints among owners of high-performance vehicles like the A 45 S AMG. The engine's high operating temperatures and pressures can wear seals and gaskets, resulting in leaks. Symptoms include low oil levels, visible oil spots under the car, or a burning oil smell. Regular monitoring of oil levels and addressing leaks promptly are essential to maintaining engine health.
Misfiring Under Load
Some owners have reported engine misfires under heavy acceleration or high load conditions. Failing ignition coils, worn spark plugs, or problems with the fuel injection system often cause this issue. Engine misfires not only reduce performance but can also damage the catalytic converter if left unresolved. Replacing faulty components and ensuring proper fuel quality are effective solutions.
Mercedes-Benz A-Class W177 A 45 S AMG Transmission Issues
The A 45 S AMG has an AMG Speedshift DCT 8-speed transmission, designed for rapid gear shifts and precise performance. Despite its advanced design, it is not immune to problems.
Gearbox Hesitation
Some owners have noted hesitation or delays in gear engagement, particularly when shifting from park to drive or during low-speed manoeuvres. This issue is often attributed to software glitches or wear in the clutch assembly. Updating the transmission control software and inspecting the clutch system can help resolve this issue.
Jerky Shifting
Jerky or rough shifts, especially at lower speeds, are another commonly reported problem. This can result from wear in the dual-clutch system or issues with the transmission fluid. Regular fluid changes and clutch assembly servicing can improve shifting smoothness and performance.
Transmission Overheating
Due to the high-performance nature of the A 45 S AMG, the transmission is subject to intense stress during aggressive driving. Overheating can occur during track use or extended periods of spirited driving. Installing a dedicated transmission cooler and avoiding prolonged high-stress driving can help prevent overheating and protect the transmission from damage.
Mercedes-Benz A-Class W177 A 45 S AMG Suspension and Steering Problems
The suspension and steering systems of the A 45 S AMG are engineered for precision and agility, but they can also develop issues over time.
Noisy Suspension
Owners have reported clunking or knocking sounds from the suspension, particularly when driving over uneven surfaces or speed bumps. Worn bushings, strut mounts, or shock absorbers often cause these noises. Replacing these components as they wear out is crucial to maintaining ride quality and handling performance.
Electronic Suspension Malfunctions
The A 45 S AMG features an adaptive suspension system that allows drivers to adjust the ride characteristics. However, some owners have experienced malfunctions in this system, resulting in error messages or a lack of response to adjustments. These issues are typically caused by faulty sensors or control modules, which may need recalibration or replacement.
Steering Rack Issues
Steering precision is a hallmark of the A 45 S AMG, but problems with the steering rack can compromise this. Symptoms include difficulty turning the wheel, excessive play, or unusual noises while steering. These issues often stem from wear in the steering components or low power steering fluid levels. Prompt inspection and servicing can prevent further complications.
Electrical and Infotainment System Faults
The advanced electrical systems in the A 45 S AMG enhance its functionality and user experience but can also be a source of frustration.
MBUX System Glitches
The Mercedes-Benz User Experience (MBUX) infotainment system highlights the A 45 S AMG, offering features like augmented reality navigation and voice commands. However, issues like unresponsive touchscreens, freezing, or Bluetooth connectivity problems have been reported. These glitches are often resolved through software updates, though persistent problems may require hardware diagnostics.
Faulty Sensors
The A 45 S AMG relies on numerous sensors for its driver assistance features, including adaptive cruise control, lane-keeping, and parking assist. Malfunctioning sensors can lead to warning lights or a failure of these systems to operate as intended. Regular calibration and ensuring sensors are free from dirt or obstructions can help maintain reliability.
Battery Drain
High-tech features in the A 45 S AMG can place significant demands on the battery, leading to premature drain. This issue is especially common in vehicles that are not driven regularly. Using a trickle charger or ensuring the vehicle is driven frequently can help maintain battery health.
Brake System Challenges
The high-performance braking system in the A 45 S AMG is designed for intense stopping power, but owners have complained about it.
Premature Brake Wear
Due to the aggressive nature of the vehicle, brake pads and rotors may wear out faster than expected, particularly with frequent spirited driving or track use. Regular inspections and the use of high-performance brake components can extend the lifespan of the braking system.
Squeaking or Squealing Brakes
Noise during braking is a common annoyance, often caused by glazed pads or worn rotors. While this issue does not necessarily indicate a safety problem, it can detract from the driving experience. Cleaning the brake components or replacing the pads and rotors resolves the noise.
Brake System Warning Lights
Warning lights related to the braking system can appear on the dashboard due to low brake fluid levels or sensor malfunctions. Promptly investigating the cause of these warnings is essential for ensuring braking performance and safety.
Mercedes-Benz A-Class W177 A 45 S AMG Cooling System Problems
The cooling system in the Mercedes-Benz A-Class W177 A 45 S AMG is designed to manage the extreme heat generated by its high-performance engine. Despite its robust engineering, issues that may affect the system’s efficiency and reliability can arise.
Coolant Leaks
Coolant leaks are common in high-performance vehicles like the A 45 S AMG. Leaks can occur in hoses, radiators, or water pumps due to the high temperatures and pressures the cooling system endures. Symptoms include:
Visible puddles of coolant under the car.
A sweet smell from the engine bay.
Frequent low coolant warnings on the dashboard.
Regular inspection and timely replacement of worn or damaged components are essential to prevent engine overheating.
Radiator Blockages
The radiator is critical for dissipating heat from the engine, but over time, it can become clogged with dirt, debris, or mineral deposits. This can reduce its efficiency, leading to higher engine operating temperatures. Symptoms include fluctuating temperature readings and overheating during heavy use. A radiator flush and high-quality coolant can help maintain proper heat exchange and prevent blockages.
Thermostat Failures
The thermostat regulates the flow of coolant through the engine, ensuring it operates within the optimal temperature range. A malfunctioning thermostat can get stuck in the open or closed position, causing the engine to either overcook or overheat. Replacing the thermostat is a straightforward fix to resolve these temperature regulation issues.
Mercedes-Benz A-Class W177 A 45 S AMG Exterior and Bodywork Issues
The Mercedes-Benz A-Class W177 A 45 S AMG's exterior is designed to be visually striking and aerodynamically efficient. However, some owners have reported problems that can affect its durability and aesthetics.
Paint Quality Concerns
Despite its premium price, some A 45 S AMG models have experienced paint peeling, chipping, or fading over time. These issues are often caused by exposure to road debris, harsh weather, or suboptimal paint application during manufacturing. Regular washing, waxing, and paint protection films can help preserve the car’s finish. For areas where damage has already occurred, touch-up paint or professional respraying may be required.
Water Leaks
Water leaks into the cabin are a common issue reported in many vehicles with sunroofs or complex window seals, including the A 45 S AMG. These leaks can occur due to worn weather seals, clogged drainage channels, or poor assembly. Symptoms include wet carpets, damp upholstery, or water pooling inside the vehicle. Ensuring drainage channels are clean and seals are inspected and replaced when necessary can help maintain a watertight cabin.
Rust and Corrosion
While Mercedes-Benz vehicles are treated to resist rust, prolonged exposure to moisture, road salt, and minor paint damage can lead to rust formation. Commonly affected areas include the undercarriage, wheel arches, and door edges. Washing the car regularly, especially during winter, and applying rust-proofing treatments can help prevent corrosion. Prompt attention to chips and scratches that expose bare metal is also critical.
Mercedes-Benz A-Class W177 A 45 S AMG Advanced Driver Assistance System (ADAS) Glitches
The Mercedes-AMG A 45 S has some of the most advanced driver assistance systems. While these features enhance safety and convenience, they can also be prone to glitches.
Lane-Keeping Assist Sensitivity
Lane-Keeping Assist, designed to keep the car centred in its lane, has been reported to be overly sensitive or occasionally fail to detect lane markings. These malfunctions can result in unnecessary steering corrections or system disengagement. Recalibrating the system and keeping the cameras and sensors clean can help improve performance.
Blind Spot Assist Failures
Blind Spot Assist is another valuable feature that provides false alerts or fails to detect vehicles in adjacent lanes. Faulty sensors, misalignment, or software glitches are often to blame. Regular maintenance and software updates are essential to ensuring the system functions as intended.
Adaptive Cruise Control (ACC) Glitches
Adaptive Cruise Control is a standout feature in the A 45 S AMG, automatically allowing the car to maintain a safe following distance. However, some owners have reported issues with inconsistent behaviour, such as sudden disengagement or failure to adjust speed appropriately. These problems are often related to sensor malfunctions or software bugs. Ensuring the system is calibrated correctly and free from obstructions can resolve most issues.
Wind Noise and Cabin Insulation Problems
The A 45 S AMG is designed to provide a quiet and comfortable cabin environment, but some owners have reported issues with wind noise and insufficient insulation.
Wind Noise at High Speeds
Wind noise is a common concern, particularly at highway speeds. This issue often results from poorly sealed windows, misaligned doors, or gaps in weather stripping. Inspecting and replacing damaged seals and ensuring proper door and window alignment can significantly reduce wind noise.
Insufficient Road Noise Insulation
While the A 45 S AMG is a performance-oriented vehicle, some drivers feel that road noise is more pronounced than expected for a car in this price range. This is particularly noticeable on rough surfaces or when using high-performance tyres. Adding soundproofing materials to the doors, wheel wells, and undercarriage can help create a quieter cabin environment.
Long-Term Durability and Reliability Concerns
As the A 45 S AMG ages, owners have noted several long-term durability issues. These are often related to the vehicle's high-performance nature and extensive use of advanced technology.
Timing Chain Stretch
Timing chain stretch is a significant issue in high-mileage A 45 S AMG models. A stretched chain can lead to engine timing problems, resulting in rough running, loss of power, or engine misfires. Replacing the timing chain is a complex but necessary procedure to prevent severe engine damage.
Turbocharger Longevity
The A 45 S AMG turbocharger operates under extreme stress, which can lead to wear over time. Symptoms of a failing turbo include a loss of power, increased exhaust smoke, or unusual whistling sounds. Regular maintenance and avoiding prolonged periods of high boost can help extend the turbo’s lifespan.
Electrical System Aging
Electrical systems, including wiring, connectors, and control modules, may develop faults as the vehicle ages. Symptoms include intermittent operation of electrical components, dashboard warning lights, or reduced functionality of advanced systems. Routine inspections and replacing worn components can help maintain the vehicle’s reliability.
Conclusion
The Mercedes-Benz A-Class W177 A 45 S AMG is a remarkable vehicle with unparalleled performance, luxury, and technology. However, like any high-performance machine, it has its share of challenges. From engine and transmission issues to ADAS glitches and bodywork concerns, understanding these common problems can help owners address them proactively and maintain their vehicles in top condition.
Trust European Auto Pro, 253 Goodwood Road, Kings Park, 5034 South Australia for expert maintenance, diagnostics, and repairs. Their experienced technicians specialize in Mercedes-Benz and AMG models, ensuring your A 45 S AMG performs at its best for years.