What are the most common Mercedes-Benz B-Class problems?
According to Au7o's analysis of 970+ owner reports, the 2018 Mercedes-Benz B-Class has 8 documented issues. The most frequently reported are: M270 Timing Chain Stretch and Cold-Start Rattle (Petrol), OM651 Diesel DPF and EGR Clogging (B180 CDI / B200 CDI), Dual-Clutch Transmission (DCT) Shudder at Low Speeds. Of these, 2 are rated critical and should be addressed promptly.
Is the Mercedes-Benz B-Class reliable?
The 2018 Mercedes-Benz B-Class has 8 known issues documented across 970+ owner reports. 2 issues are rated critical: M270 Timing Chain Stretch and Cold-Start Rattle (Petrol) and OM651 Diesel DPF and EGR Clogging (B180 CDI / B200 CDI). Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
How much does it cost to fix common Mercedes-Benz B-Class problems?
Repair costs for known Mercedes-Benz B-Class issues range from $0 to $3,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, M270 Timing Chain Stretch and Cold-Start Rattle (Petrol), typically costs $350-$1,800 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 2013-2019 Mercedes-Benz B-Class M270 Timing Chain Stretch and Cold-Start Rattle (Petrol)?
The turbo petrol M270 (and naturally-aspirated M270/M274 in B180/B200/B250) uses a two-stage timing chain whose plastic guide rails and hydraulic tensioner degrade prematurely. Owners report a loud metallic rattle for roughly 1-15 seconds on cold start that fades as oil pressure… Repairs typically run $350-$1,800. Severity: high.
What is the 2013-2019 Mercedes-Benz B-Class OM651 Diesel DPF and EGR Clogging (B180 CDI / B200 CDI)?
The 2.2L OM651 diesel in B180 CDI / B200 CDI variants is prone to diesel particulate filter (DPF) blockage and EGR-valve carbon fouling, especially on short urban trips where the exhaust never reaches regeneration temperature. Symptoms include reduced power (limp mode), increased… Repairs typically run $200-$2,500. Severity: high.
What is the 2013-2019 Mercedes-Benz B-Class Dual-Clutch Transmission (DCT) Shudder at Low Speeds?
The 7-speed dual-clutch transmission (7G-DCT) in the B-Class develops a noticeable shudder during low-speed maneuvers and from a standstill. The issue stems from clutch pack wear and adaptive software that struggles to compensate as the clutch material thins over time. Repairs typically run $200-$3,500. Severity: medium.
What is the 2013-2019 Mercedes-Benz B-Class Turbocharger Oil Feed Line Leak?
The turbo oil feed line on the M270 engine in the B-Class develops leaks at the banjo bolt connection on top of the turbocharger. Oil drips onto the hot exhaust manifold, producing a burning oil smell and visible smoke from the engine bay. Repairs typically run $300-$900. Severity: medium.
What is the 2013-2019 Mercedes-Benz B-Class Plastic Thermostat Housing Coolant Leak (M270)?
The M270/M274 petrol engines use a map-controlled, electronically actuated thermostat integrated into a plastic housing that cracks or warps with age and heat cycling, becoming a common slow coolant-leak point. Early symptoms are a sweet coolant smell from the engine bay and a gr… Repairs typically run $300-$1,000. Severity: medium.
What is the 2013-2019 Mercedes-Benz B-Class Tailgate / Boot Lock Actuator Electrical Failure?
The W246 tailgate (boot) locking system is a frequently reported electrical weak point. Corroded contacts in the lock actuator, a defective interior release lever, or water ingress from a leaking rear-washer hose cause the boot to fail to open or lock. Keyless-Go interaction and… Repairs typically run $50-$500. Severity: medium.
What is the 2013-2019 Mercedes-Benz B-Class Panoramic Sunroof Drain Clog and Water Leak?
W246 cars fitted with the panoramic glass roof suffer water ingress when the front-corner sunroof drain tubes clog with leaves and debris, or when the perimeter rubber seal wears. Owners report water entering at the front edge / A-pillar area and pooling in the footwell, with dam… Repairs typically run $0-$400. Severity: medium.
What is the 2013-2019 Mercedes-Benz B-Class Electronic Parking Brake Actuator Malfunction?
W246 owners report the electronic parking brake (EPB) sticking or showing a malfunction warning on the dashboard. The fault is typically a failing parking-brake actuator motor, corroded cables/connectors, or a software glitch in the control module. The brake may fail to release,… Repairs typically run $200-$900. Severity: medium.
