IsItAGoodCar
Reliability Guide

Common Problems with the
2012–2014 Mercedes-Benz B-Class (W246)

We've identified 3 known issues that can affect the 2012–2014 Mercedes-Benz B-Class (W246). None are considered critical, but they're worth knowing about before you buy.

3
Known Issues
0
Serious
3
Moderate
0
Minor

The 2012–2014 period has 2 more issues than the Mercedes-Benz B-Class (W246) average across all year periods.

All Known Issues

7G-DCT Gearbox Judder

ModerateGearbox & Transmission

The dual-clutch automatic can become hesitant or jerky if clutch wear is present or fluid changes have been skipped.

Most affected: B 180 d Auto, B 200 Auto, B 220 d Auto

Estimated cost: £400–£1,500Affects: 2011–2018

Typical symptoms

  • •Shuddering when pulling away
  • •Delay engaging reverse

What to inspect before you buy

  • ✓Test drive in slow-moving traffic
  • ✓Check service history for DCT fluid changes

OM651 Diesel Timing Chain Tensioner Oil Leak

ModerateEngine

The gasket on the timing chain tensioner is a frequent leak point. Oil loss can reduce tensioner pressure and lead to chain rattle and eventual stretch.

Most affected: B 180 d, B 200 d, B 220 d

Estimated cost: £200–£500Affects: 2011–2018Often appears around: 50,000–90,000 miles

Typical symptoms

  • •Oil leak on the right side of the engine block
  • •Burning oil smell
  • •Rattle on cold start

What to inspect before you buy

  • ✓Inspect the area around the tensioner for fresh oil
  • ✓Listen for chain rattle during a cold start

Water ingress in boot from rear air vent seals

ModerateElectrics & Electronics

The rear air vent seals behind the bumper can fail, allowing water into the boot. This can damage the rear SAM electrical module, causing lighting and locking faults.

Estimated cost: £100–£500Affects: 2011–2018Often appears around: Age-related

Typical symptoms

  • •Damp or wet boot floor
  • •Random rear light faults
  • •Boot locking issues

What to inspect before you buy

  • ✓Inspect the spare wheel well for damp
  • ✓Check the rear vent seals behind the bumper
  • ✓Test all rear lights and central locking

Buying Tips for the 2012 Mercedes-Benz B-Class (W246)

  • ✓Check the 7G-DCT automatic gearbox for smooth operation; missing the 3-year/30,000-mile fluid change can cause juddering and mechatronic failure.
  • ✓On the popular 1.5-litre diesel (OM607, shared with Renault), ensure the timing belt has been changed on schedule.
  • ✓Inspect the panoramic sunroof for smooth opening and check the footwells for dampness, as blocked drainage tubes are a common source of leaks.
  • ✓Listen for rattles from the interior trim, particularly around the floating infotainment screen and dashboard fascia.
  • ✓Check for warning lights relating to the DPF on diesel models used purely for short school runs or urban driving.
  • ✓Verify that the collision prevention assist radar doesn't throw random warnings on the dashboard, which can be caused by dirt or a failing sensor.
2011 Mercedes-Benz B-Class (W246)2015 Mercedes-Benz B-Class (W246)

Browse 2012–2014 Mercedes-Benz B-Class (W246) in our Directory

View MOT history, registration data, and reliability scores for 2012–2014 Mercedes-Benz B-Class (W246) vehicles.

View 2012–2014 Directory

Other Mercedes-Benz B-Class (W246) Year Periods

20112012–201420152016–20172018

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