Family SUV · 2020–2021 cars
Mercedes-Benz GLB reliability
The Mercedes-Benz GLB fails 9.7% of first MOT tests, 24% fewer MOT fails than the average car its age and mileage, based on 7,026 DVSA MOT tests from 2022 to 2024.
Checking a Mercedes-Benz GLB before you buy?
- first-time MOT fail rate (all cars: 28.4%)
- 9.7%
- first-time MOT fail rate (all cars: 28.4%)
- fails than cars of the same age and mileage
- 24% fewer
- fails than cars of the same age and mileage
- MOT tests analysed, 2022 to 2024
- 7,026
- MOT tests analysed, 2022 to 2024
- typical miles a year, from MOT readings
- 9,400
- typical miles a year, from MOT readings
MOT fail rate by age
How the Mercedes-Benz GLB ages
Each point is the share of Mercedes-Benz GLBs of that age that failed their MOT first time, against all cars of the same age.
| Age at MOT (years) | Mercedes-Benz GLB | All cars |
|---|---|---|
| 3 | 9.7% | 12.3% |
| 4 | 9.9% | 14.1% |
By year
The best and worst Mercedes-Benz GLB years
2021 cars come out best and 2020 cars worst, once age and mileage are taken into account.
Common problems
What fails most on a Mercedes-Benz GLB
Failures by area, against cars of the same age and mileage.
Fail rate by area
- Tyres4.8%3% above avg
- Lights and electrics1.6%45% below avg
- Brakes1.2%45% below avg
- Windscreen, wipers and mirrors1.1%65% below avg
- Seat belts and airbags0.7%128% above avg
- Suspension0.6%20% below avg
- Number plates and VIN0.4%62% above avg
- Exhaust, emissions and leaks0.3%48% below avg
- Body, chassis and structure0.2%49% below avg
Average for cars of the same age and mileage
Top MOT failures
- 1
Tyre cut reaching ply or cords 1.62% of tests
A cut reaching the ply or cords weakens the tyre and can cause a burst, so it must be replaced.
- 2
Tyre tread below 1.6mm 0.87% of tests
Tread below 1.6mm is illegal and reduces grip in wet conditions, so the tyre must be replaced.
- 3
Tyre ply or cords exposed 0.77% of tests
Exposed ply or cords can let the tyre fail suddenly, so the tyre must be replaced before the car is driven.
- 4
Brake pads worn below 1.5mm 0.5% of tests
Pads worn below 1.5mm lose stopping power and can damage discs, so replacement is needed before the car is driven.
- 5
Wiper blade not clearing windscreen 0.41% of tests
Wipers that do not clear the windscreen reduce visibility in rain, which is a safety risk, so replace them.
- 6
Headlamp aim set too high 0.36% of tests
Headlamps aimed too high can dazzle other drivers, and adjusting them is usually a quick job.
- 7
Airbag warning lamp shows fault 0.2% of tests
A lit airbag warning means the airbag system may not deploy in a crash, so it needs diagnosing and repairing.
- 8
Horn not working 0.19% of tests
A non-working horn removes a key warning tool for other road users, so it must be repaired before driving.
Most common advisories
Not a fail yet, but worth pricing in: these show up on a Mercedes-Benz GLB's MOT certificate most often.
- Tyre worn close to legal limit7.24%
- Brake pads wearing thin4.71%
- Tyre slightly damaged or cracking3.62%
- Child seat limits belt inspection2.82%
- Brake discs showing some wear1.94%
- Nail in tyre, monitor1.58%
Before you buy
What to check on a used Mercedes-Benz GLB
- 1
Tyre cut reaching ply or cords
A cut reaching the ply or cords weakens the tyre and can cause a burst, so it must be replaced.
- 2
Tyre tread below 1.6mm
Tread below 1.6mm is illegal and reduces grip in wet conditions, so the tyre must be replaced.
- 3
Tyre ply or cords exposed
Exposed ply or cords can let the tyre fail suddenly, so the tyre must be replaced before the car is driven.
- 4
Brake pads worn below 1.5mm
Pads worn below 1.5mm lose stopping power and can damage discs, so replacement is needed before the car is driven.
- 5
Every MOT since new
Look for the faults above coming back year after year: it shows how the car has been looked after.
- 6
The mileage record
A typical Mercedes-Benz GLB covers about 9,400 miles a year. A big gap or a drop between MOTs is a warning sign.
- 7
Finance, stolen and write-off
The records the MOT can't show. A Full Check (£9.99) covers all three before you hand over any money.
Fuel types tested
- Diesel77.8%
- Petrol22.1%
- Hybrid0.1%
Most common colours
Black, White, Grey, Blue, Red
Average engine size: 1.8 litres.
Compare
How the Mercedes-Benz GLB compares with its rivals
| Model | Fail rate | Against same-age cars |
|---|---|---|
| MG HS Exclusive | 8.3% | 29% fewer MOT fails than the average car its age |
| Mercedes-Benz GLB | 9.7% | 24% fewer MOT fails than the average car its age |
| Mercedes-Benz EQC | 10.4% | 20% fewer MOT fails than the average car its age |
| Isuzu Trooper | 38.8% | 10% fewer MOT fails than the average car its age |
| Citroën C-Crosser | 43.6% | about average for its age |
| Mitsubishi Shogun Pinin | 45.7% | 13% more MOT fails than the average car its age |
| Jeep Patriot | 50.5% | 23% more MOT fails than the average car its age |
Every family suv ranked in the family suv reliability index, or all Mercedes-Benz models.
Questions
Mercedes-Benz GLB questions, answered
Is the Mercedes-Benz GLB reliable?
On MOT results, the Mercedes-Benz GLB is better than average: it fails 9.7% of first MOT tests, 24% fewer MOT fails than the average car its age and mileage. It ranks 19 of 59 family suv models in our index.
What fails most on a Mercedes-Benz GLB MOT?
The most common MOT failures on the Mercedes-Benz GLB are tyre cut reaching ply or cords (1.62% of tests), tyre tread below 1.6mm (0.87% of tests), tyre ply or cords exposed (0.77% of tests). By area, tyres fails 4.8% of its tests.
Which Mercedes-Benz GLB year is the most reliable?
Among years with 1,000+ tests, 2021 cars do best (26% fewer MOT fails than the average car its age) and 2020 cars do worst (23% fewer MOT fails than the average car its age).
How many miles does a Mercedes-Benz GLB do a year?
A typical Mercedes-Benz GLB covers about 9,400 miles a year, from the mileage recorded at its MOTs. Check the car you're looking at against that with a free mileage check.
How do I check a Mercedes-Benz GLB before I buy it?
Enter its registration for a free check of its MOT history, mileage, ULEZ status and tax. Before you pay, a Full Check (£9.99) shows outstanding finance, stolen and write-off records.
Source: DVSA anonymised MOT test results, 2022 to 2024, class 4 vehicles aged 3 to 25, normal tests only. How we compare like with like: our methodology.
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