MOT fail rates

Mercedes-Benz SL MOT fail rate by age

How often the Mercedes-Benz SL fails its MOT at each age, compared with all cars of the same age, and what it fails on. From 70,445 DVSA MOT tests taken 2022 to 2025.

MOT data updated 22 September 2026

At 20 years, the most tested age

MOT fail rate at age 20 (n=6,607)18.4%

All cars at 20 years (n=1,845,952)42.8%

Median mileage at test73,432

All cars, median mileage103,393

5 of 201 model groups with enough tests fail less often at 20 years.

What stands out

At 4 years the Mercedes-Benz SL fails 6.3% of MOTs (1,098 tests), 7.1 points below the 13.4% for all cars that age. At 25 years it fails 19.4% (2,479 tests), 16.9 points below the 36.3% average.
The gap is widest at 17 years: 24.7 points below all cars.
Its most common structural or mechanical fail item at 20 years: Suspension ball joint worn, at 1.9 per 100 MOTs.

MOT fail rate by age

Solid line: this model. Dashed line: all cars at the same age.

Mercedes-Benz SL: share of MOT tests that failed, by age, against all cars. Ages with fewer than 1,000 tests are not shown.
Age	MOT fail rate	Tests (n)	All cars	Difference	Median mileage
4 years	6.3%	1,098	13.4%	−7.1 pts	14,975 miles
5 years	8.3%	1,717	15.3%	−7.0 pts	19,197 miles
6 years	10.6%	2,269	17.8%	−7.2 pts	23,851 miles
7 years	10.3%	2,669	20.6%	−10.4 pts	28,805 miles
8 years	9.9%	3,319	23.8%	−13.8 pts	34,162 miles
9 years	13.4%	3,828	27.1%	−13.7 pts	38,384 miles
10 years	14.3%	3,439	30.3%	−16.0 pts	42,245 miles
11 years	16.9%	2,919	33.3%	−16.4 pts	45,736 miles
12 years	17.8%	2,220	36.0%	−18.2 pts	48,098 miles
13 years	17.8%	1,537	38.3%	−20.5 pts	51,889 miles
14 years	18.0%	1,910	40.3%	−22.3 pts	56,527 miles
15 years	17.3%	2,458	41.6%	−24.3 pts	61,047 miles
16 years	18.4%	2,947	42.6%	−24.2 pts	64,963 miles
17 years	18.4%	3,605	43.1%	−24.7 pts	68,827 miles
18 years	18.5%	4,851	43.3%	−24.7 pts	71,383 miles
19 years	18.8%	6,567	43.2%	−24.4 pts	73,366 miles
20 years	18.4%	6,607	42.8%	−24.4 pts	73,432 miles
21 years	18.9%	5,503	42.1%	−23.2 pts	73,892 miles
22 years	18.6%	4,069	41.0%	−22.4 pts	74,361 miles
23 years	17.8%	2,312	39.6%	−21.9 pts	76,154 miles
24 years	18.7%	2,122	37.8%	−19.1 pts	80,478 miles
25 years	19.4%	2,479	36.3%	−16.9 pts	85,298 miles

Most common fail items at 20 years

Split into structural or mechanical items and wear items. Wear items (tyres, brake pads, wipers, bulbs) say more about upkeep than about the design.

Structural and mechanical

Fail item	Per 100 MOTs
Suspension ball joint worn Major	1.9
Rigid brake pipes: excessively corroded Major	1.7
Suspension arm ball joint dust cover: ball joint dust cover no longer prevents the ingress of dirt Major	1.4
Airbag (SRS) warning light on Major	1.2
Coil spring broken Major	1.2
Shock absorber leaking Major	1.2

Out of 6,607 MOTs. A test with two faults counts twice.

Wear and upkeep

Fail item	Per 100 MOTs
Tyre with cords exposed Dangerous	1.5
Tyre condition: has a tear, caused by separation or partial failure of its structure Dangerous	1.2
Tyre tread below 1.6 mm Dangerous	1.2
Tyre condition: has a cut in excess of the requirements deep enough to reach the ply or cords Major	1.1

Out of 6,607 MOTs. A test with two faults counts twice.

Other models at 20 years

Model	MOT fail rate	Tests (n)	All cars
Mercedes-Benz C-Class	40.8%	24,530	42.8%
Mercedes-Benz Clk	37.6%	13,220	42.8%
Mercedes-Benz E-Class	33.1%	12,942	42.8%

MOT fail rate by first-use year

Each year has its own page: the fail rate for cars first used that year at each MOT from 2022 to 2025 with at least 1,000 tests, the most common faults at that age, and the car tax and ULEZ rules for that year.

First-use year data updated 28 September 2026.

Latest MOT age with at least 1,000 tests for each first-use year.
First used	Age at test	MOT fail rate	Tests (n)	All cars
2002	21 years in 2023	18.9%	1,063	42.1%
2003	22 years in 2025	18.6%	2,264	41.0%
2004	21 years in 2025	17.0%	1,756	42.1%
2005	20 years in 2025	18.0%	1,089	42.8%
2013	12 years in 2025	18.9%	1,158	36.0%
2014	11 years in 2025	14.4%	1,081	33.3%

More on the Mercedes-Benz SL

Read this with care. A fail rate is not a measure of build quality. How far cars are driven, how they are used and how well owners maintain them all change it, and wear items such as tyres and brake pads are common fails. Compare a model only with cars of the same age. Methodology and limits.

Looking at one Mercedes-Benz SL?

These are figures for the model, not for one car. The VetTheCar Buying Report looks at a single car: its MOT tests, defects, advisories and mileage readings.

See an example report Browse the car tools

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 22 September 2026.

Not affiliated with or endorsed by DVSA. How we calculate these figures · Data sources