2005 Mercedes-Benz B-Class diesel: common problems and MOT failures

What goes wrong more than usual on a 2005 Mercedes-Benz B-Class diesel?

Parts flagged at MOT more often on the 2005 Mercedes-Benz B-Class diesel than on all cars registered in 2005.

• Drive shaft (CV) joints4.1× usual
  Mercedes-Benz B-Class

  29% All 2005 cars

  7.1%

  Failed outright at MOT: 13.9%, against 3.3% of all 2005 cars. The rest were advisories or minor defects.

  Rough price £60–£350 our estimate

  At the viewing: Drive slowly on full steering lock in both directions and listen for clicking. Look for split rubber boots behind the front wheels.

• Rigid brake pipes1.8× usual
  Mercedes-Benz B-Class

  26.5% All 2005 cars

  14.9%

  Failed outright at MOT: 2.5%, against 2.6% of all 2005 cars. The rest were advisories or minor defects.

  Rough price £100–£400 our estimate

  At the viewing: Ask to see underneath, or check the MOT advisories: corroded brake or fuel pipes get worse every year and fail the MOT when they do.

• Diesel smoke emissions9.8× usual
  Mercedes-Benz B-Class

  8.8% All 2005 cars

  0.9%

  Failed outright at MOT: 8%, against 0.8% of all 2005 cars. The rest were advisories or minor defects.

  Rough price £175–£900 (catalytic converter) ClickMechanic

  At the viewing: Look for smoke when revving the warm engine and for engine or DPF warning lights.

• Corroded fuel pipes12.7× usual
  Mercedes-Benz B-Class

  7.6% All 2005 cars

  0.6%

  Failed outright at MOT: 0%, against 0% of all 2005 cars. The rest were advisories or minor defects.

  Rough price £100–£400 our estimate

  At the viewing: Ask to see underneath, or check the MOT advisories: corroded brake or fuel pipes get worse every year and fail the MOT when they do.

• Washers2.5× usual
  Mercedes-Benz B-Class

  9.7% All 2005 cars

  3.9%

  Failed outright at MOT: 9.7%, against 3.9% of all 2005 cars. The rest were advisories or minor defects.

  Rough price £15–£60 our estimate

  At the viewing: Test the wipers and washers on every speed.

Common 2005 Mercedes-Benz B-Class diesel MOT failures and advisories

The share of 2005 Mercedes-Benz B-Class diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

• Brakes
  54% of testsRough price £150–£350

  At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

• Suspension
  40% of testsRough price £120–£400

  At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

• Lights and electrics
  34% of testsRough price £10–£80

  At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

• Tyres
  33% of testsRough price £70–£150

  At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

• Driveshafts and joints
  29% of testsRough price £60–£350

  At the viewing: On full steering lock, drive slowly and listen for clicking from the front wheels.

• Wipers, windscreen and mirrors
  16% of testsRough price £15–£250

  At the viewing: Check for chips in the driver's view, and test the wipers and washers.

Questions to ask the seller before buying a 2005 Mercedes-Benz B-Class diesel

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

1. Any recent work on the drive shaft (cv) joints? (Flagged at MOT 4.1× as often on the 2005 Mercedes-Benz B-Class diesel as on other cars the same age.)
2. Any recent work on the rigid brake pipes? (Flagged at MOT 1.8× as often on the 2005 Mercedes-Benz B-Class diesel as on other cars the same age.)
3. Any recent work on the diesel smoke emissions? (Flagged at MOT 9.8× as often on the 2005 Mercedes-Benz B-Class diesel as on other cars the same age.)
4. Can I see the service history and receipts for any big jobs?