2004 Mercedes-Benz CLK diesel: common problems and MOT failures

What goes wrong more than usual on a 2004 Mercedes-Benz CLK diesel?

Parts flagged at MOT more often on the 2004 Mercedes-Benz CLK diesel than on all cars registered in 2004.

• Ball joint2.8× usual
  Mercedes-Benz CLK

  18.6% All 2004 cars

  6.7%

  Failed outright at MOT: 10.7%, against 3.2% of all 2004 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.

• Diesel smoke emissions9.3× usual
  Mercedes-Benz CLK

  7.4% All 2004 cars

  0.8%

  Failed outright at MOT: 7%, against 0.7% of all 2004 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.

• Sub-frame2.1× usual
  Mercedes-Benz CLK

  10.9% All 2004 cars

  5.1%

  Failed outright at MOT: 0.1%, against 0.3% of all 2004 cars. The rest were advisories or minor defects.

  Rough price £300–£1,000 our estimate

  At the viewing: Look underneath at the frame the suspension bolts to. Flaky rust or holes are expensive to fix.

• Wheel bearings1.9× usual
  Mercedes-Benz CLK

  7.4% All 2004 cars

  3.8%

  Failed outright at MOT: 0.7%, against 1.4% of all 2004 cars. The rest were advisories or minor defects.

  Rough price £120–£300 (one bearing) ClickMechanic

  At the viewing: Listen for a hum or growl that changes as you steer at speed.

• Anti-roll bar5.2× usual
  Mercedes-Benz CLK

  3.1% All 2004 cars

  0.6%

  Failed outright at MOT: 0.2%, against 0.1% of all 2004 cars. The rest were advisories or minor defects.

  Rough price £100–£280 (pair of drop links) Checkatrade

  At the viewing: Drive slowly over bumps and listen for a knock or rattle from the front. Worn anti-roll bar links are a cheap fix.

Common 2004 Mercedes-Benz CLK diesel MOT failures and advisories

The share of 2004 Mercedes-Benz CLK diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

• Suspension
  55% 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.

• Brakes
  46% 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
  41% 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
  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.

• Exhaust and emissions
  17% of testsRough price £100–£1,200

  At the viewing: Look for black soot in the tailpipe, listen for blowing from the exhaust and check for engine or DPF warning lights.

• Oil and fluid leaks
  12% 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.

Questions to ask the seller before buying a 2004 Mercedes-Benz CLK 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 ball joint? (Flagged at MOT 2.8× as often on the 2004 Mercedes-Benz CLK diesel as on other cars the same age.)
2. Any recent work on the diesel smoke emissions? (Flagged at MOT 9.3× as often on the 2004 Mercedes-Benz CLK diesel as on other cars the same age.)
3. Any recent work on the sub-frame? (Flagged at MOT 2.1× as often on the 2004 Mercedes-Benz CLK diesel as on other cars the same age.)
4. Can I see the service history and receipts for any big jobs?