Mercedes-Benz SL reliability, MPG and running costs
Figures updated
The Mercedes-Benz SL is a car. In 2024 MOT tests it scored 188 for reliability (100 is average), ranking 29 of 442, and 16.0% failed first time against a UK average of 28.5%. Its most common MOT failure is coil spring (1.8% of tests).
Ranked 29 of 442 cars in the 2024 MOT Reliability League
In 2024, 13,364 Mercedes-Benz SLs aged 3 to 20 had an MOT and 16.0% failed first time (UK average 28.5%). Taking age and mileage into account, the Mercedes-Benz SL is 47% less likely to fail than the average car of the same age and mileage.
First-time fail rate
16.0%
UK 28.5%
Fail rate at 3 years
–
UK 12.7%
Average miles a year
4,300
Typical age at test: 14 years
Mercedes-Benz SL MOT failure rate by age
Most common Mercedes-Benz SL MOT faults
- Coil spring: fractured or broken1.8% of tests
- Condition: has a cut in excess of the requirements deep enough to reach the ply or cords1.5% of tests
- Condition: has ply or cords exposed1.5% of tests
- Ball joint: ball joint excessively worn1.4% of tests
- Malfunction indicator lamp: inoperative or indicates a malfunction1.3% of tests
- Condition: has a bulge, caused by separation or partial failure of its structure1.0% of tests
What the Mercedes-Benz SL fails on
| Area | Tests failing | vs similar cars |
|---|---|---|
| Tyres | 5.3% | About average |
| Suspension | 4.8% | ▼ 50% less often |
| Brakes | 3.3% | ▼ 56% less often |
| Lights and electrics | 3.1% | ▼ 75% less often |
| Exhaust and emissions | 1.7% | ▼ 53% less often |
| Visibility | 1.6% | ▼ 70% less often |
| Wheels | 0.5% | ▲ 1.8× as often |
| Seat belts and airbags | 0.4% | ▼ 67% less often |
| Body and structure | 0.4% | ▼ 91% less often |
| Steering | 0.3% | ▼ 85% less often |
What MPG does the Mercedes-Benz SL do?
Official economy for the Mercedes-Benz SL ranges from 18.7 to 39.2mpg across the 81 versions listed by the Vehicle Certification Agency (2004–2025). A typical petrol version manages 28.5mpg. Expect 10–15% less in real-world driving.
Work out a journey's fuel costHow much is road tax on a Mercedes-Benz SL?
Any Mercedes-Benz SL first registered from April 2017 pays the standard rate of £200 a year after its first year (2026/27 rates). A Mercedes-Benz SL registered between March 2001 and March 2017 is taxed on its CO2: £325 to £790 a year.
Work out tax for a specific carMercedes-Benz SL specs and running costs
Official figures for 81 versions sold in the UK between 2004 and 2025.
Fuel types
Petrol, Plug-in hybrid
Official economy
18.7–39.2 mpg
CO2
169–362 g/km
Power
310–612 PS
| Version | Fuel | Economy | CO2 | Car tax | Company car tax |
|---|---|---|---|---|---|
| SL AMG SL 43421 PS · A9 · listed 2025 | Petrol | 31.4 mpg | 205g | £200 | 37% |
| SL AMG SL 55 4MATIC+476 PS · A9 · listed 2025 | Petrol | 21.9 mpg | 293g | £200 | 37% |
| SL Maybach SL 680 Monogram Series585 PS · A9 · listed 2025 | Petrol | 20.8 mpg | 309g | £200 | 37% |
| SL AMG SL 63 4MATIC+585 PS · A9 · listed 2025 | Petrol | 21.7 mpg | 296g | £200 | 37% |
| SL AMG SL 63 S E Performance612 PS · A9 · listed 2025 | Plug-in hybrid | 28.3 mpg | 228g | £200 | 37% |
| SL Mercedes-AMG SL 43310 PS · A9 · listed 2024 | Petrol | 31.4 mpg | 205g | £200 | 37% |
| SL Mercedes-AMG SL 55 4MATIC+350 PS · A9 · listed 2024 | Petrol | 21.9 mpg | 293g | £200 | 37% |
| SL Mercedes-AMG SL 63 4MATIC+430 PS · A9 · listed 2024 | Petrol | 21.7 mpg | 296g | £200 | 37% |
| SL Mercedes-AMG SL 63 S E Performance450 PS · A9 · listed 2024 | Plug-in hybrid | 36.7 mpg | 175g | £200 | 37% |
| SL .5 SL 400367 PS · A9 · listed 2021 | Petrol | 29.7 mpg | 215g | £200 | – |
| SL .5 SL 500455 PS · A9 · listed 2021 | Petrol | 27.4 mpg | 235g | £200 | – |
| SL Roadster SL 400 with 19'' rear wheelsA9 · listed 2018 | Petrol | 36.7 mpg | 175g | £200 | – |
| SL Roadster SL 500 with 19'' rear wheelsA9 · listed 2018 | Petrol | 31.4 mpg | 205g | £200 | – |
| SL Roadster AMG SL 63 with 19'' rear wheelsA7 · listed 2018 | Petrol | 28 mpg | 234g | £200 | – |
| SL Roadster AMG SL 63 with 20'' rear wheelsA7 · listed 2018 | Petrol | 28 mpg | 234g | £200 | – |
Economy and CO2 are official NEDC (before 2018) or WLTP figures. Car tax is the yearly rate at current rates for a car first registered in the year listed, before any expensive car supplement. Company car tax is the 2026/27 benefit-in-kind rate. Showing the 15 most recent of 81 versions.
What a Mercedes-Benz SL costs to fuel
- petrol, typical official 28.5mpg…
Official figures are usually 10–15% better than real-world driving.
Work out a journey in a Mercedes-Benz SLBuying a used Mercedes-Benz SL?
Check the MOT history of the exact car: every result, advisory and mileage reading, free.
Other Mercedes-Benz models
Frequently asked questions
›Is the Mercedes-Benz SL reliable?
Its MOT record is better than average: the Mercedes-Benz SL is 47% less likely to fail than the average car of the same age and mileage, with a reliability score of 188 in our 2024 league (100 is average).
›What are common problems with the Mercedes-Benz SL?
The most common MOT fault is “Coil spring: fractured or broken”, found in 1.8% of tests.
›What MPG does the Mercedes-Benz SL do?
Official economy for the Mercedes-Benz SL ranges from 18.7 to 39.2mpg across the 81 versions listed by the Vehicle Certification Agency (2004–2025). A typical petrol version manages 28.5mpg. Expect 10–15% less in real-world driving.
›How much is road tax on a Mercedes-Benz SL?
Any Mercedes-Benz SL first registered from April 2017 pays the standard rate of £200 a year after its first year (2026/27 rates). A Mercedes-Benz SL registered between March 2001 and March 2017 is taxed on its CO2: £325 to £790 a year.
›How many Mercedes-Benz SLs fail their MOT?
16.0% of Mercedes-Benz SLs aged 3 to 20 failed their MOT first time in 2024.
Sources: DVSA anonymised MOT tests 2024, all versions of the Mercedes-Benz SL combined (Open Government Licence v3.0); official economy and CO2 from Vehicle Certification Agency data, © Crown copyright. VCA cannot accept liability for its accuracy. How we calculate the league.