Mercedes-Benz B 160 d

The Renault K9K-based OM607 uses a timing belt that must be replaced every 120,000 km or 6 years. Neglecting the change leads to snapping and severe engine damage.

Symptoms: No noticeable warning before snap -- sudden failure with no advance notice if change is overdue

The OM607 is an interference engine with a timing belt (Renault K9K). Mercedes specifies 200,000 km; Renault recommends 120,000 km for the same engine. If the belt snaps, pistons meet valves -- immediate engine destruction.

Symptoms: Usually no warning before snap; sometimes faint squealing or rattling on cold start

The Renault-based K9K diesel shows known injector weaknesses. Defective injectors cause poor combustion, increased soot production and drastically shorten DPF regeneration intervals.

Symptoms: Rough idle, power loss, black smoke, frequent DPF regeneration, fault codes for individual cylinders

With predominantly short-trip use, the injectors on the OM607 coke prematurely. Cleaning additives can delay this; replacement costs 800-1,500 EUR.

Symptoms: Rough engine running, power loss, increased consumption, black smoke on acceleration

The EGR valve on the OM607 is prone to carbon deposits with typical urban driving. On the A/B 180d with frequent short-trip use, this is one of the most commonly cited weak points.

Symptoms: Engine warning light, power loss at mid-range rpm, limp mode, fault code P0400/P0401

The 1.5-litre diesel OM607 is primarily designed for long-distance use. With predominantly urban driving and short trips under 10 km, the DPF cannot reach operating temperature for a complete regeneration.

Symptoms: DPF warning symbol, frequent prompts for motorway driving for regeneration, rising oil level through fuel dilution

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.