2003 Mercedes-Benz S-Class: common problems and MOT failures

What goes wrong more than usual on a 2003 Mercedes-Benz S-Class?

Parts flagged at MOT more often on the 2003 Mercedes-Benz S-Class than on all cars registered in 2003.

• Ball joint2× usual
  Mercedes-Benz S-Class

  12.9% All 2003 cars

  6.4%

  Failed outright at MOT: 4.1%, against 2.9% of all 2003 cars. The rest were advisories or minor defects.

  Rough price £60–£150 (one joint) ClickMechanic

  At the viewing: Listen for knocking over bumps and check the rubber boots behind the wheels aren't split.

• Airbag warning light2.5× usual
  Mercedes-Benz S-Class

  3.8% All 2003 cars

  1.5%

  Failed outright at MOT: 3.6%, against 1.3% of all 2003 cars. The rest were advisories or minor defects.

  Rough price £10–£80 our estimate

  At the viewing: Ask a friend to check every light while you work the switches: indicators, brake lights, fog lights and reversing lights.

Common 2003 Mercedes-Benz S-Class MOT failures and advisories

The share of 2003 Mercedes-Benz S-Class MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

• Brakes
  35% 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
  31% 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
  29% 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
  27% 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.

• Oil and fluid leaks
  11% of testsRough price £80–£600

  At the viewing: Look under the engine and on the ground where the car is usually parked for fresh oil or fluid.

• Wipers, windscreen and mirrors
  7% 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 2003 Mercedes-Benz S-Class

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

1. Any recent work on the ball joint? (Flagged at MOT 2× as often on the 2003 Mercedes-Benz S-Class as on other cars the same age.)
2. Any recent work on the airbag warning light? (Flagged at MOT 2.5× as often on the 2003 Mercedes-Benz S-Class as on other cars the same age.)
3. Can I see the service history and receipts for any big jobs?