How reliable is the Mercedes-Benz R-Class compared with other cars?

We do not publish a comparison for the Mercedes-Benz R-Class, because the cars of this model that have been tested do not cover a wide enough range of ages and mileages. Its raw pass rate is 72.3% across 1,730 tests, but comparing a raw rate between models mostly ranks them by how new they are rather than how good they are. The failure and advisory patterns further down the page are still drawn from real tests and are worth reading.

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

The most common advisory is "Brake pipe damaged or excessively corroded", noted on 27.2% of all Mercedes-Benz R-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 R-Class usually have at its MOT?

The average odometer reading recorded at test is 124,687 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.

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

Of the Mercedes-Benz R-Class cars tested, 92% are diesel, 8% are petrol. Fuel type affects which items tend to fail, particularly emissions and exhaust components.

Model reliability file

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

From 1,730 recorded MOT tests of the Mercedes-Benz R-Class, published by DVSA.

Data updated 29 July 2026

Quick answer

Across 1,730 MOT tests, 72.3% of Mercedes-Benz R-Class tests ended in a pass. This figure is not adjusted for age or mileage, so it is not a reliability ranking: the Mercedes-Benz R-Class fleet does not yet cover a wide enough spread of ages and distances to compare it fairly against other models. Its most commonly recorded failure is transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc, which appears in 23.3% of failed tests. Cars of this model average 124,687 miles on the odometer when tested.

At a glance

Recorded pass rate

72.3%unadjusted, not comparable1,730 tests

We are not publishing a ranking for the R-Class. The examples tested do not cover a wide enough spread of ages and mileages to compare it fairly, and an unadjusted pass rate mostly sorts models by how recently they were bought rather than how well they were built. The failure and advisory patterns below come from the same 1,730 tests and are worth reading on their own terms.

DVSA recorded wording

Most common failure items

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

1.A transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc23.3%
90 occurrencesDriveshaft CV joint gaiter split or missing explained
2.Brake pipe damaged or excessively corroded16.3%
63 occurrencesBrake pipe corroded explained
3.A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning15.2%
59 occurrencesLamp not working explained
4.Parking brake efficiency below minimum requirement14.5%
56 occurrencesParking brake efficiency too low explained
5.A tyre seriously damaged7.8%
30 occurrencesTyre damaged or deteriorated explained
6.Tyre tread depth not in accordance with the requirements7.0%
27 occurrencesTyre worn close to the legal limit explained
7.Parking brake efficiency below minimum requirement7.0%
27 occurrencesParking brake efficiency too low explained
8.A shock absorber damaged to the extent that it does not function or showing signs of severe leakage6.2%
24 occurrencesShock absorber defective explained
9.A tyre cords visible or damaged5.9%
23 occurrencesTyre ply or cord exposed, or the casing separating explained
10.A spring or spring component fractured or seriously weakened5.7%
22 occurrencesRoad spring broken or fractured explained

Warnings without a failure

Most common advisories

Share of all Mercedes-Benz R-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.Brake pipe damaged or excessively corroded27.2%
470 testsBrake pipe corroded explained
2.Tyre tread depth not in accordance with the requirements26.3%
455 testsTyre worn close to the legal limit explained
3.Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users23.4%
404 tests
4.A suspension pin, bush or joint excessively worn11.0%
190 testsSuspension arm bush worn explained
5.Brake disc or drum excessively weakened, insecure or fractured9.6%
166 testsBrake disc worn, pitted or scored explained
6.A tyre seriously damaged7.3%
127 testsTyre damaged or deteriorated explained
7.A shock absorber damaged to the extent that it does not function or showing signs of severe leakage7.2%
124 testsShock absorber defective explained
8.A brake lining or pad worn below 1.5mm6.8%
117 testsBrake drum or shoe worn or contaminated explained

What gets tested

The R-Class fleet

Average mileage recorded at test: 124,687
Fuel mix of tested cars: Diesel91.6%
Petrol8.3%

Trim names grouped into this model (2)

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

R 300
R 350 CDI

Check a specific Mercedes-Benz R-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

Common questions

How reliable is the Mercedes-Benz R-Class compared with other cars?: We do not publish a comparison for the Mercedes-Benz R-Class, because the cars of this model that have been tested do not cover a wide enough range of ages and mileages. Its raw pass rate is 72.3% across 1,730 tests, but comparing a raw rate between models mostly ranks them by how new they are rather than how good they are. The failure and advisory patterns further down the page are still drawn from real tests and are worth reading.
What is the most common MOT failure on a Mercedes-Benz R-Class?: The item recorded most often is "A transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc", which appears in 23.3% of failed Mercedes-Benz R-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 R-Class?: The most common advisory is "Brake pipe damaged or excessively corroded", noted on 27.2% of all Mercedes-Benz R-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 R-Class usually have at its MOT?: The average odometer reading recorded at test is 124,687 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.
Are most Mercedes-Benz R-Class models petrol or diesel?: Of the Mercedes-Benz R-Class cars tested, 92% are diesel, 8% are petrol. 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. No adjusted rate is shown because this model's tested examples do not cover enough of the national age and mileage range for standardisation to mean anything.

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.