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Mercedes-Benz SLK R170 (1st gen) (1996-2003) reliability

At a glance

Mercedes-Benz SLK R170 (1st gen) built before 2000: about average at the MOT

Mercedes-Benz SLK R170 (1st gen) models built before 2000 fail their MOT about as often as similar cars the same age. An independent inspection matters more than the wider numbers on cars this old.

Looking at a Mercedes-Benz SLK R170 (1st gen) right now?

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Key figure

24% of MOT tests on Mercedes-Benz SLK R170 (1st gen) models built before 2000 ended in a fail (retests included), against 22% for similar cars the same age.

Most common issue

The most common MOT issue on Mercedes-Benz SLK R170 (1st gen) models built before 2000 involves the brakes.

Mercedes-Benz SLK R170 (1st gen)
No reliability rating: too close to call between ratings1996-2003ConvertiblePETROL

Based on 11,492 tests of SLK models registered 1996-2003.

About 1 in 15 SLK R170 (1st gen) MOTs (7.4%) failed and still hadn't passed 3 days later. That's for cars built before 2000 (over 25 years old), all fuels combined.

Based on 4,205 tests (DVSA MOT results, 2025). A fail that passed a retest within 3 days, even the same day, isn't counted. Nor is a fail with no later MOT on record.

About 1 in 25 SLK R170 (1st gen) MOTs (4.2%) found at least one dangerous defect. These are cars built before 2000 (over 25 years old).

Based on 4,205 tests (DVSA MOT results, 2025). Dangerous is the most serious grade an MOT gives: a direct risk to road safety.

R170 (1st gen) fail rate by age

Below typicalAbove typicalHigh (28% or more)Highest fail rateUK average for cars this age
Age / builtFail rateMOT tests
21 yearsbuilt around 2004
80625.9%
22 yearsbuilt around 2003
2,03723.8%
23 yearsbuilt around 2002
2,07723.6%
24 yearsbuilt around 2001
2,36724.2%
25+ yearsbuilt 2000 or earlier
4,20523.9%

Fail rate is the share of MOT tests that ended in a fail. Retests count as tests. How we count fail rates Build years are worked out from age, so they are approximate. Tests counted are 2025 MOTs. Highest fail rate at 21 years old.

How the SLK R170 (1st gen) compares

At each age below, see how the SLK R170 (1st gen) holds up against other cars the same age. The averages combine all fuel types.

Based on 22,307 tests across 11 Mercedes-Benz models, built before 2000 (over 25 years old).

Below typicalAbove typicalHigh (28% or more)Highest fail rateMercedes-Benz average
Age / builtFail rateMOT tests
21 yearsbuilt around 2004
80625.9%
22 yearsbuilt around 2003
2,03723.8%
23 yearsbuilt around 2002
2,07723.6%
24 yearsbuilt around 2001
2,36724.2%
25+ yearsbuilt 2000 or earlier
4,20523.9%

Fail rate is the share of MOT tests that ended in a fail. Retests count as tests. How we count fail rates Build years are worked out from age, so they are approximate. Tests counted are 2025 MOTs.

What to check before viewing

The model's most common MOT issues, turned into things you can ask about or look for.

Brake pipes and hoses

High priority

Look under the car for corrosion or chafing on the rigid brake pipes near the rear axle.

Suspension

Worth checking

Inspect the suspension carefully and ask the seller for repair history.

Tyres

Worth checking

Check tread depth across the full width on all four; uneven wear suggests alignment or suspension issues.

Leaks

Worth checking

Inspect the leaks carefully and ask the seller for repair history.

Vehicle-specific check

Worth checking

Check the car’s number plate on MOT Wise to see its own MOT history and any recalls for its build years.

Other convertibles to compare

Other convertibles, with each one's figures taken at the same age as the SLK R170 (1st gen).

  1. 1

    Triumph TR6

    Same body type, tested at the same age

    Fail rate
    12.9%
    Fail, no pass in 3 days
    4.9%
    Dangerous
    2.4%

    Lower fail rate: 12.9%, against 23.9% for the Mercedes-Benz SLK R170 (1st gen), both built before 2000.

    1,028 MOT tests on cars built before 2000

  2. 2

    MG B

    Same body type, tested at the same age

    Fail rate
    15.5%

    Lower fail rate: 15.5%, against 23.9% for the Mercedes-Benz SLK R170 (1st gen), both built before 2000.

    Some figures could not be compared for these two cars. So this comparison uses the fail rate and recalls only.

    2,865 MOT tests on cars built before 2000

  3. 3

    TVR Chimaera

    Same body type, tested at the same age

    Fail rate
    12.5%
    Fail, no pass in 3 days
    6.3%
    Dangerous
    2.1%

    Lower fail rate: 12.5%, against 23.9% for the Mercedes-Benz SLK R170 (1st gen), both built before 2000.

    2,536 MOT tests on cars built before 2000

  4. 4

    Lotus Elise

    Same body type, tested at the same age

    Fail rate
    14.8%

    Lower fail rate: 14.8%, against 23.9% for the Mercedes-Benz SLK R170 (1st gen), both built before 2000.

    2 critical recall campaigns matching this model/build period.

    2,026 MOT tests on cars built before 2000

Fail rate
= the share of MOT tests that ended in a fail. Retests count as tests.
Fail, no pass in 3 days
= the share of MOT tests that failed and still hadn't passed 3 days later. A fail that passed a retest within 3 days, even the same day, isn't counted.
Dangerous
= the share of MOT tests where the tester marked a fault as dangerous. It is against the law to drive the car until it is fixed.

How many are still registered

93%of all Mercedes-Benz SLK cars first registered in 2014 to 2015 were still registered 10 years later. This is the whole model, not only this generation.

UK average for cars first registered in 2014 to 2015: 92% · About typical

The share still registered can reflect demand, the cost of repairs, exports, write-offs and how owners use the car. It isn't proof of how long the car lasts mechanically.

Source: DfT vehicle licensing statistics (VEH0124).

Recall context

26 recalls in all

No recall notices match this build period.

For the exact car, check GOV.UK's recall checker with the number plate.

What has gone wrong on SLK R170 (1st gen) cars built before 2000

The share of petrol cars that have ever failed an MOT on each part of the car. Based on 1,118 cars.

Structural systems

Suspension
45%
Emissions
28%
Steering
8%
Bodywork
5%

Wear items

Lighting
68%
Brakes
51%
Tyres
50%

Rust, which the MOT calls corrosion: 32% of these cars show rust-related issues at this age.

Check the sills, subframe and brake pipes before you decide.

How SLK R170 (1st gen) cars have aged

How SLK R170 (1st gen) cars have aged

How fail rates have changed as these cars got older. Each line follows cars first registered in about the same year across several years of MOT data. Not a prediction for any one car.

Some lines cover only a year or two, so read this as a rough guide.

0%10%20%1819202122232425Age at MOTBuilt around 2003, 18 years old at the time of MOT: 25.2% (1,741 tests, 2021 data)Built around 2003, 19 years old at the time of MOT: 25.0% (1,584 tests, 2022 data)Built around 2003, 20 years old at the time of MOT: 27.1% (1,475 tests, 2023 data)Built around 2003, 21 years old at the time of MOT: 25.7% (1,264 tests, 2024 data)Built around 2003, 22 years old at the time of MOT: 25.0% (1,116 tests, 2025 data)2003Built around 2002, 19 years old at the time of MOT: 24.8% (1,740 tests, 2021 data)Built around 2002, 20 years old at the time of MOT: 24.1% (1,588 tests, 2022 data)Built around 2002, 21 years old at the time of MOT: 23.6% (1,405 tests, 2023 data)Built around 2002, 22 years old at the time of MOT: 23.9% (1,304 tests, 2024 data)Built around 2002, 23 years old at the time of MOT: 24.2% (1,112 tests, 2025 data)2002Built around 2001, 20 years old at the time of MOT: 24.9% (2,142 tests, 2021 data)Built around 2001, 21 years old at the time of MOT: 24.4% (1,942 tests, 2022 data)Built around 2001, 22 years old at the time of MOT: 24.3% (1,771 tests, 2023 data)Built around 2001, 23 years old at the time of MOT: 25.4% (1,546 tests, 2024 data)Built around 2001, 24 years old at the time of MOT: 23.7% (1,339 tests, 2025 data)2001Built around 2000, 21 years old at the time of MOT: 25.7% (1,598 tests, 2021 data)Built around 2000, 22 years old at the time of MOT: 23.8% (1,423 tests, 2022 data)Built around 2000, 23 years old at the time of MOT: 23.4% (1,233 tests, 2023 data)Built around 2000, 24 years old at the time of MOT: 24.7% (1,072 tests, 2024 data)Built around 2000, 25 years old at the time of MOT: 23.7% (879 tests, 2025 data)2000Built around 1999, 22 years old at the time of MOT: 25.1% (1,165 tests, 2021 data)Built around 1999, 23 years old at the time of MOT: 24.3% (1,018 tests, 2022 data)Built around 1999, 24 years old at the time of MOT: 24.9% (853 tests, 2023 data)Built around 1999, 25 years old at the time of MOT: 23.3% (695 tests, 2024 data)1999Built around 1998, 23 years old at the time of MOT: 24.6% (946 tests, 2021 data)Built around 1998, 24 years old at the time of MOT: 25.2% (812 tests, 2022 data)Built around 1998, 25 years old at the time of MOT: 23.0% (639 tests, 2023 data)1998Built around 1997, 24 years old at the time of MOT: 25.9% (545 tests, 2021 data)Built around 1997, 25 years old at the time of MOT: 23.8% (449 tests, 2022 data)1997
First registered around 2003First registered around 2002First registered around 2001First registered around 2000
How each part holds up as R170 (1st gen) cars age

How each part holds up as R170 (1st gen) cars age

The share of petrol cars built pre-2005 that have ever failed an MOT on each part of the car. Rates usually rise with age, but can dip slightly as cars leave the road.

Part of the car21 years22 years23 years24 years
Suspension79%67%49%45%
Brakes48%52%46%47%
Emissions26%28%25%27%
Tyres58%54%54%52%
Lighting56%64%61%59%
Bodywork13%4%3%2%
Steering15%10%7%9%
Corrosion26%29%27%28%

Based on petrol cars in the pre-2005 build-year band, from 239 to 387 cars at each age.

R170 (1st gen) variants compared
All generations of this modelEnough data

Most common issues on Mercedes-Benz SLK models of this age

This list covers every Mercedes-Benz SLK built before 2000, whichever generation it is. We don't have a defect list for the R170 (1st gen) on its own.

Most common advisories and fails

In order of the share of MOT tests that recorded each one

  1. 1
    Advisory

    Brake pipe corroded or covered in grease

    18.6%
    Advisory: 1,143Fail: 89 (7% of the times it was found)
  2. 2
    Advisory

    Suspension part corroded, but not seriously weakened

    15.0%
    Advisory: 1,081Fail: 21 (2% of the times it was found)
  3. 3
    Advisory

    Oil leak, but not excessive

    13.9%
    Advisory: 667Fail: 6 (1% of the times it was found)
  4. 4
    Advisory

    Tyre slightly damaged, cracking or perishing

    13.7%
    Advisory: 839Fail: 102 (11% of the times it was found)
  5. 5
    Advisory

    Tyre worn close to the legal limit or worn on the edge

    12.9%
    Advisory: 780Fail: 48 (6% of the times it was found)

Based on 4,207 tests

Looking at a Mercedes-Benz SLK R170 (1st gen) right now?

Enter its number plate to see its full MOT history, risk rating and running costs.

Frequently asked questions

Built before 2000 (over 25 years old), the Mercedes-Benz SLK R170 (1st gen) (1996-2003) fails MOTs at about the rate typical for this age. This is based on 4,205 25+ year old MOT tests from DVSA data. Each retest counts as a test.

*The build year is worked out from the date a car was first used on UK roads. For most cars this matches when it was registered, but imports may differ by a few months.

Data sourced from DVSA MOT History API. From 11,492 MOT tests on Mercedes-Benz SLK models first registered between 1996-2003. These figures are a guide, not a guarantee.