The BMW 6 Series E64 M6 is a high-performance convertible that blends luxury with thrilling driving dynamics. Powered by the legendary 5.0-liter V10 engine (S85), the E64 M6 offers an exhilarating driving experience with its high-revving powerplant and sharp handling. However, the M6 is also known for some common issues that can arise, especially as the vehicle ages. Understanding these problems can help owners maintain their vehicles and avoid expensive repairs.
BMW 6 Series E64 M6 Engine Performance Issues
The BMW E64 M6 is powered by the S85 V10 engine, a marvel of engineering that delivers impressive power and performance. However, the S85 engine is also known for several issues that can affect its reliability and longevity. One of the most significant concerns with this engine is rod bearing wear. The S85 is known to have rod bearings that wear prematurely, which can lead to catastrophic engine failure if not addressed. Symptoms of rod bearing wear include a knocking noise from the engine, especially during cold starts, and metal shavings found in the oil during an oil change. Preventative maintenance, including regular oil changes with high-quality oil and, in some cases, a preemptive rod bearing replacement, can help mitigate this risk.
Another common issue with the S85 engine is the failure of the throttle actuators. The engine uses individual throttle bodies for each cylinder, controlled by electronic throttle actuators. Over time, the gears inside these actuators can wear out, leading to a failure in throttle control. Symptoms of failing throttle actuators include reduced engine power, rough idling, and the illumination of the "Check Engine" light. Replacing the throttle actuators is a costly repair, but it is essential to maintain the engine's performance.
The S85 engine is also prone to issues with the VANOS system, BMW's variable valve timing technology. The VANOS system helps optimize engine performance across different RPM ranges, but it can develop problems over time, particularly with the solenoids that control the system. Symptoms of VANOS issues include a loss of power, rough idling, and poor fuel efficiency. Replacing the VANOS solenoids and ensuring the system is properly maintained can help prevent these problems from worsening.
SMG Transmission Issues
The BMW E64 M6 is equipped with the SMG (Sequential Manual Gearbox) transmission, which offers a unique driving experience by combining the engagement of a manual transmission with the convenience of an automatic. However, the SMG transmission is known for certain reliability issues. One of the most common problems is related to the SMG pump, which is responsible for generating the hydraulic pressure needed to engage the gears. Over time, the SMG pump can fail, leading to difficulty in shifting gears or complete transmission failure. Symptoms of a failing SMG pump include delayed or rough shifting, warning lights on the dashboard, and, in some cases, the inability to select any gear. Replacing the SMG pump is an expensive repair, but it is crucial for the proper functioning of the transmission.
Another issue with the SMG transmission is related to the clutch. The SMG transmission uses a conventional clutch, which can wear out over time, especially if the vehicle is driven aggressively. A worn clutch can cause the transmission to slip, leading to a loss of power and poor acceleration. Replacing the clutch is a routine maintenance item but can be costly due to the labor involved.
The SMG transmission can also experience issues with the gear position sensor and the hydraulic accumulator. The gear position sensor can fail, leading to incorrect gear readings or the inability to select a gear. The hydraulic accumulator, which stores hydraulic pressure, can also fail, leading to shifting problems. Regular maintenance of the SMG transmission, including fluid changes and inspections, can help prevent these issues from becoming more severe.
Electrical System Problems
The BMW 6 Series E64 M6 is equipped with a sophisticated electrical system that controls various aspects of the vehicle, from the engine and transmission to the infotainment and climate control systems. While this system offers a high level of functionality and convenience, it also increases the likelihood of electrical issues arising. One common problem reported by owners is related to the vehicle's battery and charging system. The M6 is known to experience battery drain issues, where the battery loses charge even when the car is not in use. This can be due to various reasons, including faulty wiring, malfunctioning control modules, or issues with the comfort access system, which allows for keyless entry and ignition.
The alternator, responsible for charging the battery while the engine is running, is another component prone to failure in the M6. A failing alternator can lead to a battery that doesn't hold a charge, resulting in a car that struggles to start or maintain electrical functions. Symptoms of a failing alternator include dimming headlights, flickering dashboard lights, and warning messages related to the charging system. If the alternator fails completely, the vehicle may lose power altogether, leaving the driver stranded. Regular checks of the battery and charging system, including testing the alternator's output, can help prevent these issues from occurring.
In addition to battery and charging system problems, the E64 M6 is also prone to issues with its numerous sensors and control units. These sensors and control units monitor and control various aspects of the vehicle's operation, and when they malfunction, they can trigger warning lights on the dashboard, even when there is no underlying mechanical issue. For example, the tire pressure monitoring system (TPMS) is known to give false readings, indicating a tire is low on pressure when it is not. Similarly, the engine control module (ECM) can store fault codes related to the fuel system or emissions control system, even when there is no actual problem. These electrical gremlins can be difficult and expensive to diagnose and fix, as they often require specialized equipment and expertise to address properly.
Suspension and Steering Issues
The suspension and steering system in the BMW 6 Series E64 M6 is designed to provide a precise and responsive driving experience, but it is not without its issues. One of the most commonly reported problems is related to the suspension components, particularly the control arm bushings and ball joints. Over time, these parts can wear out, leading to a noticeable clunking noise when driving over bumps or during sharp turns. Worn bushings and ball joints can also cause the vehicle to feel less stable and precise, especially at higher speeds, as the worn components allow for more movement in the suspension than intended. This can lead to uneven tire wear, poor handling, and a less comfortable ride. In some cases, the entire control arm assembly may need to be replaced to restore proper handling and ride quality.
The E64 M6 is also equipped with an Electronic Damper Control (EDC) system, which allows the driver to adjust the suspension settings for different driving conditions. However, the EDC system can develop issues, particularly with the electronic dampers. Over time, the dampers can leak or fail, leading to a harsh or bouncy ride. Symptoms of failing dampers include a noticeable decrease in ride comfort, poor handling, and increased body roll during cornering. If the dampers fail completely, the vehicle may become difficult to control, particularly during aggressive driving. Regular inspections of the suspension system, including the control arms, bushings, and dampers, are essential to maintain the vehicle's handling characteristics.
Steering problems have also been reported by some M6 owners. The E64 is equipped with a hydraulic power steering system, which provides precise and responsive steering but can develop issues over time. One common problem is with the power steering pump, which can develop leaks or fail, leading to a loss of power assist and making the steering wheel difficult to turn, especially at low speeds. If the power steering fluid level becomes too low due to a leak, it can cause the power steering pump to overheat and fail, leading to a complete loss of power steering. Regular inspections of the steering system, including checking for leaks and ensuring the power steering fluid is at the correct level, are essential to maintain the vehicle's steering performance.
Cooling System Failures
The cooling system in the BMW 6 Series E64 M6 is another area where problems can arise, particularly as the vehicle accumulates mileage. The S85 V10 engine generates a significant amount of heat, and the cooling system is designed to manage this heat effectively. However, the cooling system's components, including the electric water pump, thermostat, and radiator, can develop issues over time.
One of the most common problems is with the electric water pump, which is responsible for circulating coolant throughout the engine to prevent overheating. Unlike traditional mechanical water pumps, the electric pump in the E64 M6 is prone to failure, often without much warning. When this happens, the engine can quickly overheat, leading to potential damage to the cylinder head, head gasket, or even the engine block. Symptoms of a failing water pump include the engine temperature rising rapidly, coolant leaks, and warning lights related to the cooling system appearing on the dashboard.
In addition to the water pump, the thermostat is another component of the cooling system that can fail. The thermostat regulates the engine's temperature by controlling the flow of coolant, and if it becomes stuck in the open or closed position, it can cause the engine to run too hot or too cold. This can affect performance and fuel efficiency and lead to increased wear on the engine components. Replacing the thermostat as part of regular cooling system maintenance can help prevent this issue from occurring.
The cooling system in the E64 M6 also includes several plastic components, such as the radiator, coolant hoses, and expansion tank, which can become brittle and crack over time. These components are particularly prone to failure in older vehicles or those that have been exposed to extreme temperatures. If any of these components fail, it can lead to coolant leaks and the risk of overheating. Regular maintenance of the cooling system, including timely replacement of the water pump, thermostat, and coolant, can help prevent these issues and keep the engine running at the proper temperature.
Fuel System Problems
The fuel system in the BMW 6 Series E64 M6, while generally reliable, can develop issues that affect the vehicle's performance and drivability. One common problem is related to the fuel injectors, which can become clogged or leak over time. Clogged fuel injectors can lead to uneven fuel delivery, causing the engine to run lean, which can result in increased exhaust emissions, reduced fuel economy, and potential damage to the catalytic converter. On the other hand, leaking injectors can cause the engine to run rich, leading to black smoke from the exhaust, poor fuel economy, and increased wear on the engine components. In some cases, the injectors may need to be cleaned or replaced to restore proper function.
Another fuel system issue that can occur is related to the fuel pump. The fuel pump is responsible for delivering fuel from the tank to the engine, and if it fails, it can lead to a loss of power, engine stalling, or even a no-start condition. Symptoms of a failing fuel pump include difficulty starting the engine, hesitation during acceleration, and a noticeable drop in performance. If the fuel pump is not replaced promptly, it can lead to more serious issues, such as damage to the fuel injectors or engine components.
The fuel filter is another component of the fuel system that can cause problems if it becomes clogged with debris. A clogged fuel filter can restrict fuel flow to the engine, causing a loss of power and efficiency. If the fuel filter is not replaced regularly, it can lead to more serious issues, such as damage to the fuel pump or fuel injectors. Regular maintenance of the fuel system, including timely replacement of the fuel injectors, fuel pump, and fuel filter, is essential to avoid these problems and ensure the vehicle continues to run smoothly.
Conclusion
The BMW 6 Series E64 M6 is a high-performance convertible that offers an exhilarating driving experience with its powerful V10 engine and sharp handling. However, like any performance car, it is not without its common problems. From engine performance issues and SMG transmission failures to cooling system problems and electrical system glitches, these issues can be costly and inconvenient if not addressed promptly. Regular maintenance and attention to the early signs of trouble can help keep these problems at bay and ensure that your M6 continues to deliver the performance and luxury that BMW is known for. If you’re experiencing any of these issues or need expert advice and service, visit our workshop, European Auto Pro, located at 253 Goodwood Road, Kings Park, 5034 South Australia. Our team of skilled technicians is here to help you maintain your BMW in top condition.