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

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

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

• Drive shaft (CV) joints3.3× usual
  Mercedes-Benz A-Class

  23.3% All 2005 cars

  7.1%

  Failed outright at MOT: 10.8%, 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.

• Diesel smoke emissions7.1× usual
  Mercedes-Benz A-Class

  6.4% All 2005 cars

  0.9%

  Failed outright at MOT: 5.9%, 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.

• Washers2.2× usual
  Mercedes-Benz A-Class

  8.7% All 2005 cars

  3.9%

  Failed outright at MOT: 8.7%, 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.

• Flexible brake hoses1.8× usual
  Mercedes-Benz A-Class

  10.3% All 2005 cars

  5.6%

  Failed outright at MOT: 0.6%, against 1.2% of all 2005 cars. The rest were advisories or minor defects.

  Rough price £50–£200 our estimate

  At the viewing: Look for cracked or bulging rubber hoses behind the wheels and in the engine bay.

• Corroded fuel pipes6.3× usual
  Mercedes-Benz A-Class

  3.8% 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.

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

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

• Brakes
  48% 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.

• Lights and electrics
  38% of testsRough price £10–£80

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

• Suspension
  36% 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.

• Tyres
  35% 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
  23% 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
  15% of testsRough price £15–£250

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

Known faults on the 2005 Mercedes-Benz A-Class diesel

Reported by owners, mechanics and buying guides for this model and age. Check which engine the car has, as some apply to one engine only.

• Poor reliability: suspension and electrical faults

  All engines

  Faults were incredibly common, especially suspension and electrical ones, and the average repair bill was over £500.

  At the viewing: Get a pre-purchase inspection, listen for suspension knocks and test every electrical item.

  Source: What Car?: used Mercedes-Benz A-Class (2005-2012) reliability

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

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

1. What has gone wrong and been fixed?
2. Any recent work on the drive shaft (cv) joints? (Flagged at MOT 3.3× as often on the 2005 Mercedes-Benz A-Class diesel as on other cars the same age.)
3. Any recent work on the diesel smoke emissions? (Flagged at MOT 7.1× as often on the 2005 Mercedes-Benz A-Class diesel as on other cars the same age.)
4. Any recent work on the washers? (Flagged at MOT 2.2× as often on the 2005 Mercedes-Benz A-Class diesel as on other cars the same age.)
5. Can I see the service history and receipts for any big jobs?