Mercedes-Benz B 220 CDI

Over 100,000 vehicles recalled: the chain tensioner seal leaks, allowing engine oil to drip onto the exhaust system and potentially ignite.

Symptoms: Dropping oil level, oil smell from engine bay, oily deposits under the vehicle, possible oil fire

The OM651 uses a simplex timing chain. With short-trip driving and overdue oil change intervals the chain stretches.

Symptoms: Light rattling noise on cold start from the rear of the engine, no fault code stored

Same Delphi piezo injector problems as in the DE18: 220 CDI and 250 CDI variants affected. Mercedes replaced them with solenoid injectors as part of a service action.

Symptoms: Vibrations and rough running especially under acceleration, elevated fuel consumption

The EGR cooler of the OM651 develops hairline cracks at the connection stub and loses coolant. Green staining next to the fuel filter under the engine cover is typical.

Symptoms: Dropping coolant level without visible leak, intermittent coolant warning, green spots under the vehicle, heater output diminishing

The DMF on the OM651 suffers under the high torque output. Documented case: all 8mm rivets sheared at 149,000 km, with consequential damage to the clutch and crankshaft speed sensor.

Symptoms: Rattling and juddering at warm idle, vibrations when pulling away, shuddering at low RPM, noise increases with warm engine

From around 150,000–180,000 km the OM651 turbocharger leaks oil through worn bearings, which drips onto the EKAS intake port deactivation actuator and destroys it. Double damage.

Symptoms: Black smoke under acceleration, oil residue in charge air hose, power loss, fault code P0299 boost pressure underrun

Vehicles with 7G-DCT from the period January 2018 to March 2020 may have insufficient gearbox oil. Possible drivetrain failure and increased fire risk. Recall action carried out.

Collision warning system incorrectly detects obstacles in urban traffic and initiates autonomous emergency braking. Software update resolves the problem. Rear light failures also known.

Corroded connectors on the ECU cause failure of ESP, ABS and PRE-Safe. Safety systems are deactivated, vehicle goes into limp mode.

Door lower edges of the W246 rust, though less severely than the predecessor. Axle springs and components corrode and can break through oxidation. Rust susceptibility inappropriate for the price level.

A/C condensers can develop leaks and lose refrigerant. A/C cooling diminishes after several years. Problem less frequent than on the predecessor W245 but still present.

7G-DCT dual clutch gearbox shifts too hectically and causes increased clutch wear in stop-and-go traffic. Clutch replacement costs approximately €1,500. Shift behaviour criticised as rough.