Common problems
Mercedes-Benz SL common problems
What MOT testers find on the Mercedes-Benz SL: the parts that fail or get advisories most often at each age, against all cars of the same age. From 70,445 DVSA MOT tests taken 2022 to 2025.
MOT data updated
At 20 years, the most tested age
What stands out
- No part area of the Mercedes-Benz SL fails more than 1 point per 100 MOTs above all cars at 20 years old (n=6,607; all cars n=1,845,952).
- Lights and electrics fails are less common: 4.5 per 100 MOTs against 21.2 for all cars at the same age.
- The fail item testers record most often at 20 years: suspension ball joint worn, on 1.6 per 100 MOTs (all cars 2.3).
- The most common advisory or minor defect: rigid brake pipes: corroded, covered in grease or other material, on 10.2 per 100 MOTs.
Problems by part at 20 years
How many of every 100 MOTs found a fail, or an advisory or minor defect, in each area. A test with faults in two areas counts in both.
| Area | Fails | All cars | Advisories | All cars |
|---|---|---|---|---|
| Suspension | 6.8 | 16.5 | 18.0 | 35.2 |
| Brakes | 4.6 | 13.5 | 22.2 | 33.7 |
| Lights and electrics | 4.5 | 21.2 | 5.0 | 17.4 |
| Tyres | 3.9 | 6.4 | 17.8 | 26.1 |
| Windscreen, wipers and mirrors | 2.1 | 7.6 | 3.8 | 6.4 |
| Exhaust, emissions and leaks | 1.6 | 7.0 | 5.3 | 15.6 |
| Seat belts and airbags | 1.5 | 3.1 | 0.2 | 1.5 |
| Body and structure | 0.9 | 9.2 | 2.0 | 15.6 |
| Steering | 0.8 | 4.2 | 2.3 | 6.5 |
| Number plates and VIN | 0.6 | 0.7 | 1.6 | 6.3 |
| Road wheels | 0.4 | 0.4 | 0.9 | 1.1 |
What testers fail most on the SL at 20 years
| Item | Area | Per 100 MOTs | All cars | Typical repair (estimate) |
|---|---|---|---|---|
| Suspension ball joint worn | Suspension | 1.6 | 2.3 | £75 to £237 per side (rough guide) |
| Airbag (SRS) warning light on | Seat belts and airbags | 1.4 | 1.4 | diagnosis from £39 (rough guide) |
| Suspension arm ball joint dust cover: ball joint dust cover no longer prevents the ingress of dirt | Suspension | 1.2 | 1.1 | £75 to £237 per side (rough guide) |
| Tyre with cords exposed | Tyres | 1.2 | 1.5 | £88 to £145 per tyre |
| Coil spring broken | Suspension | 1.2 | 2.6 | £64 to £236 per spring (rough guide) |
| Rigid brake pipes: excessively corroded | Brakes | 1.1 | 2.5 | £137 to £392 per car (rough guide) |
| Shock absorber leaking | Suspension | 1.1 | 1.2 | £122 to £484 per axle (pair) (rough guide) |
| Wipers not clearing screen | Windscreen, wipers and mirrors | 0.8 | 3.4 | £15 to £30 per blade |
| Dipped headlight not working | Lights and electrics | 0.8 | 1.9 | £18 to £86 per lamp |
| Tyre tread below 1.6 mm | Tyres | 0.8 | 2.6 | £88 to £145 per tyre |
Early warnings: advisories and minor defects at 20 years
Advisories and minor defects are recorded, but the car still passes. Across all cars, a part with an advisory or minor defect failed at the next MOT 5.5 times in 100 (n=88,666,940 pairs of consecutive MOTs), against 0.3 times in 100 when the same part had none (n=12,936,860,350).
| Item | Area | Per 100 MOTs | All cars | If it needs replacing (estimate) |
|---|---|---|---|---|
| Rigid brake pipes: corroded, covered in grease or other material | Brakes | 10.2 | 15.2 | £137 to £392 per car (rough guide) |
| Tread depth: worn close to legal limit/worn on edge | Tyres | 9.9 | 15.7 | £88 to £145 per tyre |
| Brake discs: worn, pitted or scored, but not seriously weakened | Brakes | 6.9 | 10.7 | £148 to £376 per axle (rough guide) |
| Tyre condition: slightly damaged/cracking or perishing | Tyres | 6.1 | 10.2 | £88 to £145 per tyre |
| Brake pads: wearing thin | Brakes | 4.6 | 5.7 | £72 to £174 per axle (rough guide) |
| Suspension arm ball joint: ball joint has slight play | Suspension | 4.6 | 2.7 | £75 to £237 per side (rough guide) |
| Engine oil leaks: leak, but not excessive | Exhaust, emissions and leaks | 4.5 | 14.1 | |
| Wheel bearings: has slight play | Suspension | 3.6 | 1.6 | £103 to £276 per wheel (rough guide) |
| Shock absorbers: has light misting of oil | Suspension | 3.6 | 3.3 | £122 to £484 per axle (pair) (rough guide) |
| Suspension arm pins and bushes: pin or bush worn but not resulting in excessive movement | Suspension | 3.4 | 7.7 | £92 to £237 per arm (rough guide) |
Repair estimates are a guide for an independent garage: labour at the national median local garage rate (median £78 an hour from 65 garages, ONS price quotes) times estimated labour hours, plus a parts band. Labour hours and most parts bands are estimates, not quotes, and prices vary by model, engine and region. A warning light fault shows the cost of the diagnosis only.
How problems change with age
| Age | Tests (n) | Suspension | Brakes | Lights and electrics |
|---|---|---|---|---|
| 4 years | 1,098 | 0.2 | 0.3 | 0.8 |
| 5 years | 1,717 | 0.6 | 0.2 | 1.3 |
| 6 years | 2,269 | 1.1 | 0.4 | 1.9 |
| 7 years | 2,669 | 1.4 | 0.5 | 1.3 |
| 8 years | 3,319 | 1.5 | 0.7 | 1.5 |
| 9 years | 3,828 | 2.5 | 1.1 | 2.1 |
| 10 years | 3,439 | 3.4 | 1.8 | 2.2 |
| 11 years | 2,919 | 4.0 | 2.7 | 2.7 |
| 12 years | 2,220 | 5.0 | 2.0 | 3.6 |
| 13 years | 1,537 | 5.5 | 2.1 | 4.7 |
| 14 years | 1,910 | 5.5 | 3.3 | 4.0 |
| 15 years | 2,458 | 5.6 | 3.4 | 3.3 |
| 16 years | 2,947 | 6.3 | 4.2 | 3.9 |
| 17 years | 3,605 | 7.1 | 4.4 | 3.9 |
| 18 years | 4,851 | 7.0 | 4.3 | 3.9 |
| 19 years | 6,567 | 6.9 | 5.0 | 4.4 |
| 20 years | 6,607 | 6.8 | 4.6 | 4.5 |
| 21 years | 5,503 | 5.9 | 5.3 | 5.3 |
| 22 years | 4,069 | 5.8 | 4.5 | 5.9 |
| 23 years | 2,312 | 5.4 | 4.0 | 6.3 |
| 24 years | 2,122 | 5.0 | 4.1 | 7.7 |
| 25 years | 2,479 | 5.4 | 3.6 | 9.0 |
Mileage
At 20 years, Mercedes-Benz SL cars showing 30,000 to 60,000 miles failed 12.7% of MOTs (n=1,727); the band that failed most, 90,000 to 120,000 miles, failed 23.5% (n=1,428). For pass and fail rates by age, see Mercedes-Benz SL MOT fail rates.
What to check on a viewing
On the Mercedes-Benz SL, testers most often record suspension ball joint worn; airbag (SRS) warning light on; suspension arm ball joint dust cover: ball joint dust cover no longer prevents the ingress of dirt. Look at these first, then the areas below.
Suspension
- Listen for knocks or clonks over speed bumps and rough roads on the test drive.
- Push down hard on each corner: the car should settle at once rather than keep bouncing.
- Look behind the wheels for broken or heavily rusted coil springs and split rubber bushes.
- Check that the car sits level and that no tyre is worn on one edge only.
Brakes
- On the test drive the car should stop in a straight line without pulling, juddering or grinding.
- Look at the discs through the wheels for a deep lip, heavy rust or scoring.
- Check that the handbrake or electronic parking brake holds the car on a slope.
- Ask when the pads, discs and brake fluid were last changed, and for the receipts.
Lights and electrics
- With someone outside, try every light: dipped and main beam, indicators, brake lights, fog lights and number plate lamps.
- Check that the warning lights come on with the ignition and go out once the engine runs.
- Look for misted, cracked or yellowed headlamp lenses.
Ask for the car's MOT history and service record: advisories that repeat from one year to the next show what has been left. GOV.UK MOT history.
Questions
What are the most common problems on the Mercedes-Benz SL?
At 20 years, the age with the most MOT tests (6,607), the fail items testers record most often on the Mercedes-Benz SL are suspension ball joint worn (1.6 per 100 MOTs), airbag (SRS) warning light on (1.4 per 100 MOTs), suspension arm ball joint dust cover: ball joint dust cover no longer prevents the ingress of dirt (1.2 per 100 MOTs). The most common advisories or minor defects are rigid brake pipes: corroded, covered in grease or other material (10.2) and tread depth: worn close to legal limit/worn on edge (9.9).
Which parts of the Mercedes-Benz SL fail more often than on other cars?
None by more than 1 point per 100 MOTs at 20 years, compared with 1,845,952 MOTs of all cars the same age.
Mercedes-Benz SL problems by area
More on the Mercedes-Benz SL
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The all cars figures cover all class 4 vehicles (cars and light vans) tested at the same age.
Looking at a Mercedes-Benz SL?
These figures describe the model, not the car in front of you. Found one you might buy? See what the VetTheCar Buying Report covers, or use the tools that work without a registration.
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Repair estimates: ONS consumer price quotes for local garage labour (09/2025 to 08/2026), the MOT inspection manual for defect wording, and estimated labour hours and parts bands. Not affiliated with or endorsed by ONS.
Source
Contains public sector information licensed under the Open Government Licence v3.0. Source: DVSA anonymised MOT test data, class 4 normal MOT tests, 2022 to 2025. MOT data updated 28 September 2026.
Not affiliated with or endorsed by DVSA. How we calculate these figures · Data sources