Mercedes-Benz SL common problems and MOT failures

What usually goes wrong with a Mercedes-Benz SL?

We haven’t found widely reported faults for the Mercedes-Benz SL in the UK buying guides we use yet. That doesn’t mean it has none, so check the car carefully and look at the MOT weak spots below.

Common Mercedes-Benz SL MOT failures to check

Parts flagged at MOT well above the usual rate for cars the same age, in more than one year. From the DVSA’s results for every MOT done in Great Britain during 2023–2025.

• Ball joint dust cover

  up to 3.5× usual

  Stands out on cars registered in 1994, 1997, 1998, 1999, 2000 and 2001.

  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.

• Side repeaters

  up to 3.3× usual

  Stands out on cars registered in 1995, 1996, 1997, 1998, 1999 and 2000.

  Rough price £10–£80 our estimate

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

• Ball joint

  up to 3.4× usual

  Stands out on cars registered in 2016, 2017 and 2018.

  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.

• Sub-frame

  up to 2.6× usual

  Stands out on cars registered in 1994 and 1997.

  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.

• Wheels

  up to 2.4× usual

  Stands out on cars registered in 2012 and 2015.

  Rough price £70–£150 our estimate

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

• Rigid brake pipes

  up to 1.8× usual

  Stands out on cars registered in 2013 and 2014.

  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.

Mercedes-Benz SL MOT pass rate by year

Of the years since 2005 with plenty of MOT tests, the 2008 Mercedes-Benz SL did best (83% passed first time, 26 points above all 2008 cars) and the 2019 did worst (92%, 7 points above all 2019 cars). Older cars fail more, so compare each year with all cars registered the same year.

Questions to ask the seller before buying a Mercedes-Benz SL

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 dust cover? (Flagged at MOT 3.5× as often on the Mercedes-Benz SL as on other cars the same age.)
2. Any recent work on the side repeaters? (Flagged at MOT 3.3× as often on the Mercedes-Benz SL as on other cars the same age.)
3. Any recent work on the ball joint? (Flagged at MOT 3.4× as often on the Mercedes-Benz SL as on other cars the same age.)
4. Can I see the service history and receipts for any big jobs?