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Sports car and convertible · 1996–2020 cars

Mercedes-Benz SLK reliability

The Mercedes-Benz SLK fails 25.9% of first MOT tests, 21% fewer MOT fails than the average car its age and mileage, based on 216,164 DVSA MOT tests from 2022 to 2024.

Better than averageReliability score 69/100#40 of 62 sports car and convertibles

Checking a Mercedes-Benz SLK before you buy?

first-time MOT fail rate (all cars: 28.4%)
25.9%
first-time MOT fail rate (all cars: 28.4%)
fails than cars of the same age and mileage
21% fewer
fails than cars of the same age and mileage
MOT tests analysed, 2022 to 2024
216,164
MOT tests analysed, 2022 to 2024
typical miles a year, from MOT readings
5,500
typical miles a year, from MOT readings

What this means for buyers

The Mercedes-Benz SLK has 21% fewer MOT fails than cars of the same age and mileage. Its first-time MOT fail rate is 25.9%, against 28.4% for all cars. Across 216,164 tests from 2022 to 2024, it ranks 40 of 62 sports car and convertible models. The 2011 model year is the strongest, with 31% fewer MOT fails than cars of the same age and mileage, while 1997 is the weakest with 9% fewer.

A middling rank doesn't rule the SLK out. It can still be a good buy if you check the right things. Start with the suspension and tyres, where the most common MOT failures sit. Look for coil springs that are fractured or broken, which appear in 3.89% of tests. Then check the suspension ball joints for excessive wear, the tyre tread for anything below 1.6mm, and the tyres for exposed ply or cords.

MOT fail rate by age

How the Mercedes-Benz SLK ages

Each point is the share of Mercedes-Benz SLKs of that age that failed their MOT first time, against all cars of the same age.

0%12.5%25%37.5%50%581114172023Age at MOT (years)
Mercedes-Benz SLKAll cars
Mercedes-Benz SLK first-time MOT fail rate by age
Age at MOT (years)Mercedes-Benz SLKAll cars
513.3%16.4%
612.7%19.1%
715.1%22.1%
817.7%25.5%
919.5%28.8%
1021%31.8%
1121.9%34.6%
1223.4%37.3%
1328%39.5%
1429.6%41.1%
1529.8%42.3%
1630.5%42.9%
1731.1%43.4%
1832.5%43.5%
1932%43.4%
2031.5%42.8%
2131%41.4%
2230.5%40.6%
2330.9%38.9%
2431.8%37.1%
2530.6%35.8%

By year

The best and worst Mercedes-Benz SLK years

2011 cars come out best and 1997 cars worst, once age and mileage are taken into account.

Mercedes-Benz SLK MOT results by year of first registration
First registeredTestsFail rateAgainst same-age carsTypical mileage
2016 SLK4,62813.5%24% fewer fails35,780
2015 SLK18,81815.9%22% fewer fails42,078
2014 SLK18,86418%24% fewer fails48,557
2013 SLK17,84521.5%21% fewer fails55,601
2012 SLK21,81821.9%25% fewer fails57,629
2011 SLK9,62720.7%31% fewer fails55,025
2010 SLK7,58228%15% fewer fails59,750
2009 SLK9,15929.5%17% fewer fails64,966
2008 SLK11,81029%23% fewer fails69,988
2007 SLK13,12630.6%20% fewer fails71,132
2006 SLK13,76131.1%21% fewer fails75,705
2005 SLK18,01631.3%22% fewer fails78,628
2004 SLK11,51033.9%17% fewer fails81,009
2003 SLK6,16833.4%18% fewer fails81,441
2002 SLK6,82730%25% fewer fails84,542
2001 SLK7,81830.8%22% fewer fails87,439
2000 SLK6,92230.3%21% fewer fails88,520
1999 SLK6,40831.6%13% fewer fails86,922
1998 SLK4,02031.4%11% fewer fails87,748
1997 SLK1,37531.7%9% fewer fails90,010

Common problems

What fails most on a Mercedes-Benz SLK

Failures by area, against cars of the same age and mileage.

Fail rate by area

  • Suspension10.5%6% below avg
  • Lights and electrics7.9%43% below avg
  • Tyres5.8%2% above avg
  • Brakes5.8%31% below avg
  • Windscreen, wipers and mirrors2.9%48% below avg
  • Exhaust, emissions and leaks2.4%43% below avg
  • Body, chassis and structure1.4%73% below avg
  • Seat belts and airbags1.2%22% below avg
  • Steering0.8%64% below avg

Average for cars of the same age and mileage

Top MOT failures

  1. 1

    Coil spring fractured or broken 3.89% of tests

    A broken coil spring can leave the car sitting low or unstable, so it must be replaced before driving.

  2. 2

    Suspension ball joint excessively worn 2% of tests

    A worn ball joint can fail and cause loss of steering control, so it must be replaced promptly.

  3. 3

    Tyre tread below 1.6mm 1.74% of tests

    Tread below 1.6mm is illegal and reduces grip in wet conditions, so the tyre must be replaced.

  4. 4

    Tyre ply or cords exposed 1.32% of tests

    Exposed ply or cords can let the tyre fail suddenly, so the tyre must be replaced before the car is driven.

  5. 5

    Rigid brake pipe excessively corroded 1.28% of tests

    Badly corroded brake pipes can leak or fail, which can cause a loss of braking, so repair is urgent.

  6. 6

    Stop lamp not working 1.16% of tests

    A failed stop lamp means drivers behind cannot see when you brake, a safety risk that must be fixed.

  7. 7

    Engine warning light inoperative or lit 1.07% of tests

    An engine warning light that is lit or not working can hide faults, so diagnosis is needed before buying.

  8. 8

    Position lamp not working 1.06% of tests

    A failed position lamp makes the car harder to see in poor light and is illegal, so it must be repaired.

Most common advisories

Not a fail yet, but worth pricing in: these show up on a Mercedes-Benz SLK's MOT certificate most often.

  • Tyre worn close to legal limit11.67%
  • Brake pipes corroded and greasy8.77%
  • Tyre slightly damaged or cracking6.13%
  • Brake disc pitted or scored5.77%
  • Brake pads wearing thin3.91%
  • Wheel bearing slight play3.56%

Before you buy

What to check on a used Mercedes-Benz SLK

  1. 1

    Coil spring fractured or broken

    A broken coil spring can leave the car sitting low or unstable, so it must be replaced before driving.

  2. 2

    Suspension ball joint excessively worn

    A worn ball joint can fail and cause loss of steering control, so it must be replaced promptly.

  3. 3

    Tyre tread below 1.6mm

    Tread below 1.6mm is illegal and reduces grip in wet conditions, so the tyre must be replaced.

  4. 4

    Tyre ply or cords exposed

    Exposed ply or cords can let the tyre fail suddenly, so the tyre must be replaced before the car is driven.

  5. 5

    Every MOT since new

    Look for the faults above coming back year after year: it shows how the car has been looked after.

  6. 6

    The mileage record

    A typical Mercedes-Benz SLK covers about 5,500 miles a year. A big gap or a drop between MOTs is a warning sign.

  7. 7

    Finance, stolen and write-off

    The records the MOT can't show. A Full Check (£9.99) covers all three before you hand over any money.

Fuel types tested

  • Petrol75.7%
  • Diesel24.3%
  • LPG0%
  • Electric0%
  • Other0%

Most common colours

Silver, Black, White, Blue, Red

Average engine size: 2.3 litres.

Compare

How the Mercedes-Benz SLK compares with its rivals

Mercedes-Benz SLK against similar models
ModelFail rateAgainst same-age cars
Porsche 91110.4%62% fewer MOT fails than the average car its age
Mercedes-Benz SL15.3%51% fewer MOT fails than the average car its age
Porsche Boxster16.4%48% fewer MOT fails than the average car its age
BMW Z422.2%33% fewer MOT fails than the average car its age
Audi TT22.6%29% fewer MOT fails than the average car its age
Mercedes-Benz SLK25.9%21% fewer MOT fails than the average car its age
Mazda MX-525.3%16% fewer MOT fails than the average car its age

Every sports car and convertible ranked in the sports car and convertible reliability index, or all Mercedes-Benz models.

Questions

Mercedes-Benz SLK questions, answered

Is the Mercedes-Benz SLK reliable?

On MOT results, the Mercedes-Benz SLK is better than average: it fails 25.9% of first MOT tests, 21% fewer MOT fails than the average car its age and mileage. It ranks 40 of 62 sports car and convertible models in our index.

What fails most on a Mercedes-Benz SLK MOT?

The most common MOT failures on the Mercedes-Benz SLK are coil spring fractured or broken (3.89% of tests), suspension ball joint excessively worn (2% of tests), tyre tread below 1.6mm (1.74% of tests). By area, suspension fails 10.5% of its tests.

Which Mercedes-Benz SLK year is the most reliable?

Among years with 1,000+ tests, 2011 cars do best (31% fewer MOT fails than the average car its age) and 1997 cars do worst (9% fewer MOT fails than the average car its age).

How many miles does a Mercedes-Benz SLK do a year?

A typical Mercedes-Benz SLK covers about 5,500 miles a year, from the mileage recorded at its MOTs. Check the car you're looking at against that with a free mileage check.

How do I check a Mercedes-Benz SLK before I buy it?

Enter its registration for a free check of its MOT history, mileage, ULEZ status and tax. Before you pay, a Full Check (£9.99) shows outstanding finance, stolen and write-off records.

Source: DVSA anonymised MOT test results, 2022 to 2024, class 4 vehicles aged 3 to 25, normal tests only. How we compare like with like: our methodology.

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