Is the Mercedes-Benz S-Class reliable?

On MOT evidence the Mercedes-Benz S-Class is well above average. It passes 84.7% of tests once age and mileage are accounted for, against a national average of 72.3%, which ranks it 21 of 262 models with enough data for a fair comparison. This measures how often the car meets the MOT standard, not how often it breaks down or what a repair costs.

What is the most common MOT failure on a Mercedes-Benz S-Class?

The item recorded most often is "A suspension pin, bush or joint excessively worn", which appears in 24.7% of failed Mercedes-Benz S-Class tests. Because one failed test can list several items, these shares do not add up to 100%.

What do testers most often warn about on a Mercedes-Benz S-Class?

The most common advisory is "Tyre tread depth not in accordance with the requirements", noted on 21.8% of all Mercedes-Benz S-Class tests. An advisory is not a failure: it flags something that will likely need attention before the next test.

What mileage does a Mercedes-Benz S-Class usually have at its MOT?

The average odometer reading recorded at test is 93,840 miles. This is the mileage across all tested examples of every age, not an annual figure, so treat it as a description of the fleet rather than a target for one car.

Does a Mercedes-Benz S-Class get harder to pass as it ages?

Yes. At 3 to 5 years old, 92.3% of Mercedes-Benz S-Class tests pass. By fifteen years or more, that falls to 75.2%. Nearly every model follows this pattern, which is why comparing raw pass rates between models is misleading unless age is accounted for.

Are most Mercedes-Benz S-Class models petrol or diesel?

Of the Mercedes-Benz S-Class cars tested, 66% are diesel, 26% are petrol, 7% are hybrid. Fuel type affects which items tend to fail, particularly emissions and exhaust components.

Model reliability file

Mercedes-Benz S-Class MOT pass rate & common failures

From 25,269 recorded MOT tests of the Mercedes-Benz S-Class, published by DVSA.

Data updated 29 July 2026

Quick answer

The Mercedes-Benz S-Class passes 84.7% of MOT tests once results are adjusted for the age and mileage of the cars tested, against a national average of 72.3%. That is well above average, ranking it 21 of 262 models with enough data to compare fairly. Based on 25,269 tests. Its most commonly recorded failure is suspension pin, bush or joint excessively worn, which appears in 24.7% of failed tests. Cars of this model average 93,840 miles on the odometer when tested.

At a glance

Pass rate, adjusted for age and mileage

84.7%national average72.3%unadjusted83.6%range covered99%rank21 of 262

The S-Class is 12.4 percentage points above the national pass rate once age and mileage are accounted for, which is well above average. The unadjusted figure is 83.6%; the difference is what the age and mileage of this model’s fleet was hiding.

DVSA recorded wording

Most common failure items

Share of failed Mercedes-Benz S-Class tests in which each item was recorded. One failed test often lists several items, so these do not sum to 100%.

1.A suspension pin, bush or joint excessively worn24.7%
847 occurrencesSuspension arm bush worn explained
2.Tyre tread depth not in accordance with the requirements16.9%
580 occurrencesTyre worn close to the legal limit explained
3.A tyre cords visible or damaged10.7%
366 occurrencesTyre ply or cord exposed, or the casing separating explained
4.A tyre seriously damaged8.8%
302 occurrencesTyre damaged or deteriorated explained
5.A suspension pin, bush or joint excessively worn7.7%
265 occurrencesSuspension arm bush worn explained
6.Brake pipe damaged or excessively corroded7.2%
248 occurrencesBrake pipe corroded explained
7.Parking brake efficiency below minimum requirement6.2%
212 occurrencesParking brake efficiency too low explained
8.A brake lining or pad worn below 1.5mm6.2%
211 occurrencesBrake drum or shoe worn or contaminated explained
9.A suspension joint dust cover missing or no longer prevents the ingress of dirt etc5.5%
188 occurrencesSuspension joint dust cover missing or split explained
10.Wiper blade missing or obviously not clearing the windscreen5.5%
187 occurrencesWiper or washer not working properly explained

Warnings without a failure

Most common advisories

Share of all Mercedes-Benz S-Class tests carrying each advisory. The denominator differs from the failure list above because an advisory can be issued on a car that passed.

1.Tyre tread depth not in accordance with the requirements21.8%
5,500 testsTyre worn close to the legal limit explained
2.Brake disc or drum excessively weakened, insecure or fractured10.2%
2,586 testsBrake disc worn, pitted or scored explained
3.Brake pipe damaged or excessively corroded9.6%
2,416 testsBrake pipe corroded explained
4.A brake lining or pad worn below 1.5mm7.4%
1,867 testsBrake drum or shoe worn or contaminated explained
5.A suspension pin, bush or joint excessively worn7.1%
1,792 testsSuspension arm bush worn explained
6.Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users5.6%
1,409 tests
7.A tyre seriously damaged4.7%
1,192 testsTyre damaged or deteriorated explained
8.Brake disc or drum significantly and obviously worn4.5%
1,128 testsBrake disc worn, pitted or scored explained

How wear changes the picture

Pass rate by vehicle age

3–5 yrs92%

6–8 yrs89%

9–11 yrs87%

12–14 yrs80%

15+ yrs75%

Bands holding too few tests to be meaningful are omitted rather than shown as a rate.

What gets tested

The S-Class fleet

Average mileage recorded at test: 93,840
Fuel mix of tested cars: Diesel66.3%
Petrol25.7%
Hybrid7.3%
Diesel hybrid0.6%

Trim names grouped into this model (30)

Recorded exactly as DVSA holds them. Trim-level names are rolled up so one model is not split across a dozen thin pages.

S 350
S 350 AMG LINE D AUTO
S 350 AMG LINE PREMIUM D AUTO
S 350 D
S 350 D L AMG LINE AUTO
S 350 D L AMG LINE EXEC PREM+A
S 350 D L AMG LINE PREMIUM + A
S 350 L AMG LINE PREM D MHEV A
S 350 L AMG LINE PREM EXEC D A
S 350 L AMG LINE PREMIUM D A
S 350 L AMG LN PREM + EXEC D A
S 400
S 400 L AMG LINE PREM + D 4M A
S 400 L AMG LN LUX LOUNGE D A
S 400 L AMG LN PRM+EXEC D 4M A
S 430
S 450
S 450 AMG LINE PREM MHEV 4M A
S 450 L AMG LN PREM + D MHEV A
S 500
S 500 AMG LINE MHEV 4MATIC A
S 500 AMG LINE PREM MHEV 4M A
S 500 L
S 500 L AMG LINE PRM+MHEV 4M A
S 500 L AMG LN PREM MHEV 4M A
S 580 L AMG LINE PREM EXEC E A
S 580 L AMG LINE PREMIUM + E A
S 580 L AMG LN PREM + EXEC E A
S-CLASS 300 SEL
S-CLASS AMG LINE

Check a specific Mercedes-Benz S-Class

A model average tells you the pattern. Its own MOT record tells you the car.

Compare within the range

Other Mercedes-Benz models

Mercedes-Benz A-Class — 73.3% adjusted
Mercedes-Benz C-Class — 77.0% adjusted
Mercedes-Benz E-Class — 78.5% adjusted
Mercedes-Benz GLA — 82.3% adjusted
Mercedes-Benz Vito — 71.0% adjusted
Mercedes-Benz GLC — 85.9% adjusted
All Mercedes-Benz models

Similar test volumes

Compare against other makes

Kia Soul — 71.1% adjusted, ranked 159
Nissan NV200 — 60.0% adjusted, ranked 252
Seat Alhambra — 73.2% adjusted, ranked 133
Alfa Romeo Giulietta — 69.8% adjusted, ranked 172

Common questions

Is the Mercedes-Benz S-Class reliable?: On MOT evidence the Mercedes-Benz S-Class is well above average. It passes 84.7% of tests once age and mileage are accounted for, against a national average of 72.3%, which ranks it 21 of 262 models with enough data for a fair comparison. This measures how often the car meets the MOT standard, not how often it breaks down or what a repair costs.
What is the most common MOT failure on a Mercedes-Benz S-Class?: The item recorded most often is "A suspension pin, bush or joint excessively worn", which appears in 24.7% of failed Mercedes-Benz S-Class tests. Because one failed test can list several items, these shares do not add up to 100%.
What do testers most often warn about on a Mercedes-Benz S-Class?: The most common advisory is "Tyre tread depth not in accordance with the requirements", noted on 21.8% of all Mercedes-Benz S-Class tests. An advisory is not a failure: it flags something that will likely need attention before the next test.
What mileage does a Mercedes-Benz S-Class usually have at its MOT?: The average odometer reading recorded at test is 93,840 miles. This is the mileage across all tested examples of every age, not an annual figure, so treat it as a description of the fleet rather than a target for one car.
Does a Mercedes-Benz S-Class get harder to pass as it ages?: Yes. At 3 to 5 years old, 92.3% of Mercedes-Benz S-Class tests pass. By fifteen years or more, that falls to 75.2%. Nearly every model follows this pattern, which is why comparing raw pass rates between models is misleading unless age is accounted for.
Are most Mercedes-Benz S-Class models petrol or diesel?: Of the Mercedes-Benz S-Class cars tested, 66% are diesel, 26% are petrol, 7% are hybrid. Fuel type affects which items tend to fail, particularly emissions and exhaust components.

How this was worked out

Method and limits

Figures come from the DVSA anonymised MOT testing dataset, published under the Open Government Licence. Only class 4 initial tests are counted: retests are excluded so a car appears once, and abandoned tests are excluded entirely. The adjusted rate is directly standardised across twenty-five age and mileage bands and reweighted onto the national distribution, so this model is compared against cars that have lived a similar life rather than against a younger or lighter-used fleet.

An MOT measures whether a car met a legal standard on the day. It is not a breakdown record, a service history or a running-cost estimate, and a pass rate is a property of a fleet rather than a prediction about one car.