Mercedes-Benz B 180 d
Renault-based small diesel, new generation. Economical with SCR catalyst, but still with little power reserve. Automatic only.
Comfort Diesel MPV
85 kW and DCT in the B-Class MPV: pleasant and economical — no fun, but no hardship.
Engine Weaknesses 5
Like its Renault counterpart, the OM608 uses a timing belt. Prescribed change every 120,000 km or 6 years -- frequently forgotten as Mercedes buyers are accustomed to timing chains.
Symptoms: No warning on snap -- sudden engine failure and severe engine damage
The OM608 (Renault K9K base) uses a timing belt. Mercedes specifies 200,000 km change interval; Renault prescribes 120,000 km for the same engine. A snap causes immediate total damage on this interference engine.
Symptoms: No noticeable warning before snap; beforehand: faint squealing, occasionally starting difficulties
The Renault-based OM608 1.5 CDI sometimes shows increased oil consumption from early on due to a leaking turbocharger shaft seal. Oil mist in the intake tract behind the turbo.
Symptoms: Dropping oil level, oil mist or blue smoke from exhaust, oil in air filter housing behind turbo
As a Renault K9K derivative, the OM608 shares the known EGR valve weakness. With frequent short-trip use, soot particles accumulate, the valve seizes and triggers limp mode.
Symptoms: Engine warning light, power loss, limp mode at around 3000 rpm, increased fuel consumption
With predominantly short-trip use, the OM608 is prone to DPF blockage. Regeneration intervals shorten until active regeneration is no longer sufficient and the filter must be manually regenerated or replaced.
Symptoms: DPF warning light, frequent active regeneration, fuel dilution in oil, power loss
Vehicle Weaknesses 7
On B-Class W247 with DCT gearbox (production Jan. 2018 – Mar. 2020) the gearbox may have been underfilled with oil. This can lead to drivetrain failure and increased fire risk.
On the B-Class W247, the collision warning system can incorrectly detect an obstacle and initiate full emergency braking even when no obstacle is present. Caused by incorrect radar sensor calibration.
According to the TÃœV report, on the W247 suspension components such as springs, shock absorbers and track rod ends are above-average causes for rejection at the main inspection.
MOT reports cite springs, dampers and track rod ends as common weak points on the W247. The parking brake also causes repeated problems.
On the B-Class W247, vibrations in the cockpit at high revs are reported, frequently caused by a dirty cabin air filter. Boot lining also rattles.
The MBUX system in the B-Class W247 shows sporadic synchronisation problems with Mercedes me as well as failures of the automatic high beam and traffic sign recognition.
Electromechanical locking modules fail after 50,000-70,000 km due to moisture damage or microswitch wear.