The Mercedes-Benz B-Class W245 B 170 is a compact MPV (multi-purpose vehicle) that combines practicality, luxury, and the engineering prowess that Mercedes-Benz is renowned for. While it is a reliable and versatile vehicle, the B 170 has been associated with a number of recurring problems over the years. This comprehensive guide explores the common issues owners face, delves into their causes, and provides potential solutions to ensure a smooth ownership experience.
Mercedes-Benz B-Class W245 B 170 Engine Performance Issues
The Mercedes-Benz B-Class W245 B 170 is powered by a naturally aspirated four-cylinder engine, offering reasonable power and efficiency. However, several common engine-related problems have been reported.
Rough Idling and Misfires
One of the most frequently reported issues with the B 170’s engine is rough idling and misfires. These symptoms often occur due to faulty spark plugs, ignition coils, or clogged fuel injectors. Misfires can cause poor engine performance, increased emissions, and reduced fuel economy. Regular spark plug replacement, proper maintenance of the ignition system, and cleaning or replacing fuel injectors can resolve these issues.
In some cases, the problem may also stem from carbon buildup on the intake valves, common in engines with direct fuel injection. A professional intake cleaning service can restore proper airflow and improve engine performance.
Excessive Oil Consumption
Excessive oil consumption is another issue plagued by some B 170 models. This problem is typically caused by worn piston rings or valve seals, allowing engine oil to seep into the combustion chamber. Symptoms include frequent oil top-ups and visible blue smoke from the exhaust. Timely diagnosis and repair, such as replacing the worn components, are essential to prevent further engine damage.
Timing Chain Noise
The timing chain in the B 170 is designed for durability, but over time, it can stretch or wear out, leading to a rattling noise from the engine. A stretched timing chain can cause engine timing issues and severe engine damage if ignored. Replacing the timing chain and tensioners is necessary to restore smooth engine operation.
Mercedes-Benz B-Class W245 B 170 Transmission Problems
Depending on the variant, the W245 B 170 is equipped with either a continuously variable transmission (CVT) or a traditional manual gearbox. Both have their own set of common issues.
CVT Jerking and Slipping
Many B 170 owners with CVT-equipped models report jerking, hesitation, or slipping during acceleration. These issues are often caused by wear and tear on the CVT belt or problems with the transmission fluid. Ensuring the transmission fluid is replaced at the recommended intervals and using the manufacturer-approved fluid can help prevent such issues. In severe cases, the CVT belt or internal components may require replacement.
Clutch Problems in Manual Variants
Clutch problems such as slipping, difficulty shifting gears, or a stiff clutch pedal are common for manual variants. These issues are typically caused by a worn clutch disc or pressure plate. Replacing the clutch components can restore smooth operation.
Transmission Control Module (TCM) Failures
Some B 170 models have experienced failures in the transmission control module (TCM), which can lead to erratic gear changes or the transmission getting stuck in a specific gear. Updating or replacing the TCM often resolves these problems.
Mercedes-Benz B-Class W245 B 170 Suspension and Steering Issues
The suspension and steering systems in the W245 B 170 are designed to provide comfort and precision. However, wear and tear over time can lead to several common issues.
Suspension Knocking Sounds
A common complaint among B 170 owners is knocking or clunking sounds from the suspension, particularly when driving over rough roads or speed bumps. These noises are usually caused by worn-out suspension components such as bushings, ball joints, or shock absorbers. Replacing these components is necessary to restore ride comfort and reduce noise.
Power Steering Problems
Power steering issues, such as stiffness or excessive noise when turning the wheel, are frequently reported. These problems are often caused by low power steering fluid levels, leaks in the hydraulic system, or a failing power steering pump. Inspecting the system for leaks and replacing worn components can resolve these issues.
Uneven Tire Wear
Uneven tyre wear is a sign of suspension misalignment or worn components. This issue affects the vehicle’s handling and increases tyre replacement costs. Regular wheel alignments and inspections of suspension components can prevent uneven tyre wear and ensure a smoother ride.
Mercedes-Benz B-Class W245 B 170 Electrical System and Electronics Faults
The Mercedes-Benz B-Class W245 B 170 has various electrical features, but these systems can be prone to malfunctions.
Instrument Cluster Issues
Some B 170 owners have reported problems with the instrument cluster, such as flickering or complete failure of the display. These issues are often caused by faulty connections or a failing instrument cluster module. Repairing or replacing the module usually resolves the problem.
Central Locking System Failures
Recurring failures in the central locking system, including doors not locking or unlocking properly, are often linked to faulty door actuators or wiring issues. Replacing the actuators or repairing the wiring can restore proper function.
Battery Drain
Battery drain is another common complaint, often caused by electrical components such as alternators, starter motors, or parasitic drains from electronic systems. Diagnosing the source of the drain and replacing faulty components are essential to prevent repeated battery issues.
Brake System Challenges
The B-Class W245 B 170 braking system is critical for safety, but it has faced several common issues.
Premature Brake Wear
Premature brake wear is among the most frequently reported issues, particularly in urban driving. The brake pads and rotors wear out faster than expected, often requiring replacement sooner. Using high-quality aftermarket brake components and ensuring proper driving habits can reduce wear and tear.
Brake Pedal Vibration
A vibrating brake pedal, especially when braking at higher speeds, is a sign of warped brake rotors. This problem can occur due to excessive heat buildup during braking. Replacing the warped rotors and pads and ensuring proper braking techniques can resolve this issue.
Brake Warning Lights
Low brake fluid levels, worn brake pads, or faulty sensors can trigger dashboard brake warning lights. Regular brake system inspections and prompt addressing of these issues are crucial for maintaining braking efficiency.
Cooling System Problems
The cooling system in the Mercedes-Benz B-Class W245 B 170 is essential for maintaining optimal engine temperature and preventing overheating. Despite its robust design, owners have commonly reported several issues.
Coolant Leaks
Coolant leaks are a frequently encountered problem in the B 170. These leaks can occur in various cooling system parts, including the radiator, water pump, and hoses. Symptoms include visible coolant puddles under the vehicle, low coolant levels, and engine overheating. If left unaddressed, coolant leaks can lead to severe engine damage. Regular inspections and timely replacement of leaking components, such as cracked hoses or failing water pumps, are necessary to maintain the system’s integrity.
Thermostat Failures
The thermostat regulates the flow of coolant through the engine, ensuring it operates at the correct temperature. A malfunctioning thermostat may get stuck in the open or closed position, causing the engine to overcool or overheat. Overcooling can reduce fuel efficiency, while overheating can cause significant engine damage. Replacing the thermostat is often a straightforward solution to these problems.
Radiator Blockages
Over time, dirt, debris, and mineral deposits can accumulate in the radiator, restricting coolant flow and reducing the system’s efficiency. Symptoms of a blocked radiator include inconsistent engine temperature readings and overheating under load. Regularly flushing the radiator and using high-quality coolant can prevent blockages and ensure the cooling system operates effectively.
Exterior and Bodywork Problems
The exterior of the B-Class W245 B 170 is designed for both style and functionality, but several issues have been noted that can affect its aesthetics and durability.
Paint Peeling and Chipping
Paint quality has been a common area of concern for B 170 owners. Peeling, chipping, and fading are often reported, particularly in areas exposed to harsh weather conditions or road debris. These issues detract from the vehicle’s appearance and can lead to rust if left untreated. Regular washing, waxing, and applying protective coatings can help maintain the paint's integrity. Addressing small chips and scratches with touch-up paint can prevent further damage.
Water Leaks
Water intrusion into the cabin is another recurring issue, particularly around the sunroof, windows, or door seals. Worn or damaged seals and clogged drainage channels are the primary culprits. Water leaks can lead to damp interiors, unpleasant odours, and potential damage to electronic components. Inspecting seals regularly and ensuring that drainage channels are clear can help prevent leaks. Replacing worn or damaged seals is essential for maintaining a watertight cabin.
Rust Development
Rust and corrosion concern older B 170 models, especially in regions with harsh climates or road salt usage. The undercarriage, wheel arches, and door edges are common areas where rust can appear. Regular washing, especially during winter months, and applying rust-proof treatments can help prevent corrosion. For existing rust spots, prompt treatment and repainting are recommended to preserve the vehicle’s structural integrity.
Mercedes-Benz B-Class W245 B 170 Advanced Safety Feature Glitches
The Mercedes-Benz B-Class W245 B 170 has several safety features to enhance driver confidence and passenger security. However, some of these systems have been reported to malfunction.
ABS and ESP Warning Lights
The Anti-lock Braking System (ABS) and Electronic Stability Program (ESP) are critical for maintaining control during braking and cornering. Some owners have reported warning lights for these systems appearing intermittently on the dashboard. These issues are often caused by faulty wheel speed sensors or issues with the control modules. Diagnosing and replacing the faulty components can restore proper system functionality.
Parking Sensor Malfunctions
Parking sensors are valuable for assisting drivers in tight spaces, but they can occasionally fail to function correctly. Common symptoms include false alarms or sensors not detecting obstacles. Dirt, debris, or faulty sensors are typical causes of this issue. Cleaning the sensors and replacing any damaged ones can resolve the problem.
Airbag System Warnings
Another reported issue is airbag system warnings on the dashboard. These warnings can be triggered by faulty sensors, loose wiring connections, or issues with the airbag control module. Prompt inspection and repair are essential to ensure the airbag system remains operational in case of an accident.
Wind Noise and Insulation Problems
While the B-Class W245 B 170 offers a comfortable and quiet ride under normal conditions, some owners have reported issues with wind noise and cabin insulation.
Excessive Wind Noise
Excessive wind noise, especially at highway speeds, has been a common complaint. This issue is often caused by poorly sealed windows, misaligned doors, or gaps in the weather stripping. Replacing worn seals and properly aligning doors and windows can reduce wind noise and improve cabin comfort.
Insufficient Sound Insulation
Road noise and vibrations can sometimes penetrate the cabin more than expected for a Mercedes-Benz vehicle. This is particularly noticeable on rough roads or at higher speeds. Adding soundproofing materials to the doors, floor, and wheel wells can significantly enhance cabin insulation and reduce noise levels.
Long-Term Reliability Concerns
Several long-term reliability concerns have been noted as the Mercedes-Benz B-Class W245 B 170 ages. These issues are typically the result of wear and tear and can impact the overall ownership experience.
Fuel Pump Failures
Fuel pump failures are a recurring issue in older B 170 models. A failing fuel pump can lead to difficulty starting the engine, reduced power, or stalling. Replacing the fuel pump is usually necessary to resolve this problem. Using high-quality fuel and performing regular maintenance can help prolong the pump’s lifespan.
Alternator and Starter Motor Wear
Electrical components such as the alternator and starter motor can wear out over time. A failing alternator may cause the battery to drain quickly, while a faulty starter motor can lead to starting difficulties. Replacing these components when they show signs of failure is essential to maintaining the vehicle’s reliability.
Aging Suspension Components
Over time, suspension components such as bushings, struts, and control arms can wear out, reducing ride quality and handling precision. Regular inspections and replacing worn components are necessary to keep the suspension system functioning optimally.
Conclusion
The Mercedes-Benz B-Class W245 B 170 is a practical and luxurious compact MPV, but it is not without its challenges. From engine performance issues to transmission problems, electrical faults, and bodywork concerns, understanding these common problems can help owners and prospective buyers make informed decisions.
For expert diagnostics, repairs, and maintenance, visit European Auto Pro, 253 Goodwood Road, Kings Park, 5034 South Australia. Their experienced technicians specialize in Mercedes-Benz vehicles, ensuring your B-Class remains reliable and enjoyable for years.