Model Reports 4 min read Updated 18 Oct 2026

BMW 6 Series 2018: reliability & common MOT faults

In 2025, 86 in every 100 first MOTs on a 2018 BMW 6 Series were passes. Most common reason for a fail: Tyre condition (front).

Summary

The 2018 BMW 6 Series follows the pattern of the model years either side.

At a glance

How 2,168 first tests went in 2025.

Passed first time
86 in every 100
Did not pass first time
14 in every 100294 failed first-attempt tests
The typical car
7 yearsabout 60,237 miles
First tests counted
2,168

What failed most often

  1. Tyre condition (front)21 in every 100 failed tests

How we count this. Data: UK MOT open data, 2025. Only Class 4 cars on their first MOT of the year are counted. A car that fails and is fixed at the test station still counts as a fail in the first-attempt rate. These are raw results, not adjusted for age, mileage, or peer mix. The MOT does not test engine or gearbox internals.

Note:

These are patterns across 2018 BMW 6 Series vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. A wear pattern follows age and use more than the way the car was built. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.

Body and structure

One fault: drive shaft joints and boots (front), 3.4 times as often as on similar cars.

Figures below are measured across the 283 of 294 failed first attempts (96.3%) that recorded an odometer reading in 2025. Mileage is needed to compare like with like. 3.7% of failures are excluded because no mileage was recorded, so treat these shares as indicative for this model year.

We only list faults with at least 20 failures and a rate of about 2.0 times that of similar cars, which keeps one-off results out of the list.

Drive shaft joints and boots (front)

Failed on 27 first tests3.4 times as often as similar carsPossible evidence

What it means

A constant velocity boot that is only severely deteriorated is Minor. It is Major once it is missing, split or insecure so that it no longer prevents the ingress of dirt. A transmission joint excessively worn is Major, and graded Dangerous when it is so worn it is likely to fail.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Tyres

Two wear patterns. The strongest is the tyre condition (front): 2.2 times as often as on similar cars.

Tyre condition (front)

Failed on 60 first tests2.2 times as often as similar carsWear pattern

What it means

Exposed or damaged ply or cords are graded Dangerous. A cut in excess of the requirements and deep enough to reach the ply or cords is Major, and testers may open the cut with a blunt instrument to check its depth. A tyre contacting the vehicle through flexing or suspension movement is not a defect; fouling fails only at the time of test.

Tyre condition (rear)

Failed on 51 first tests2.0 times as often as similar carsWear pattern

What it means

Exposed or damaged ply or cords are graded Dangerous. A cut in excess of the requirements and deep enough to reach the ply or cords is Major, and testers may open the cut with a blunt instrument to check its depth. A tyre contacting the vehicle through flexing or suspension movement is not a defect; fouling fails only at the time of test.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

MOT pass rates

How first tests ended, and how the pass rates are counted.

Passed first time
86in every 100
Passed on the first test.
Fixed at the station
2in every 100
Failed, then fixed at the test station the same day.
Failed
12in every 100
Did not pass, and were not fixed at the test station.

First-attempt pass 86.4% of 2,168 first tests (2025): only cars that passed first time count. Official-style pass 87.9%: cars fixed at the test station also count as a pass. The 2 fixed and the 12 not fixed make the 14 in every 100 that did not pass first time.

Petrol and diesel

First testsTypical mileagePassed first time, as testedPassed first time, same mileage
Diesel1,58762,978 miles8686
Petrol58053,619 miles8988

Figures are in every 100 first tests. Cars with more miles usually fail more often, so the same-mileage figure gives every fuel the mileage mix of all the cars in this year.

Same model, other years

Passed first time in every 100, all tested in 2025.

4060801002005201020152018Older cars
40608010020102018Older cars

Newer cars are younger, so look for a jump rather than the climb.

YearPassed first timeFirst tests
200470 in every 100917
200569 in every 1001,113
200670 in every 1001,283
200774 in every 1001,081
200876 in every 100980
200975 in every 100530
201080 in every 100493
201177 in every 100583
201278 in every 1001,360
201379 in every 1001,784
201478 in every 1001,816
201582 in every 1001,820
201685 in every 1001,726
201784 in every 1001,254
2018 This car86 in every 1002,168
201988 in every 100990

If you are buying one

What this year's MOT record means for the decision in front of you.

Mileage makes a modest difference on a 2018 BMW 6 Series.

Of 2018 BMW 6 Series vehicles with under 43,000 miles, 91 in every 100 passed their 2025 MOT first time. With 81,000 miles or more, 84 in every 100 did.

Under 43,000438 tests
91
43,000–54,000410 tests
89
54,000–66,000 Typical car441 tests
86
66,000–81,000403 tests
83
81,000 and over437 tests
84

Petrol or diesel?

Typical mileagePassed first time,
as tested		Passed first time,
same mileage
Diesel62,978 miles8686
Petrol53,619 miles8988

Figures are in every 100 first tests. Petrol cars look better on the raw figures only because diesel cars have done more miles (typically 62,978 against 53,619). At the same mileage there is no clear difference between the two.

What to check at your mileage

How often each fault turned up on a failed first test, by the car's mileage. Read it as: what is likely to need looking at on a car like the one in front of you.

Under 43,00054,000–66,00081,000 and over
Tyre condition (front)2.53.42.5

Faults per 100 first tests, by the car's mileage at the test.

Every figure here is a first-attempt MOT rate from DVSA open data for this model line, for cars of this model year tested in 2025. Each mileage band holds a fifth of the tests. MOTs do not test engine or gearbox internals, so this is a pre-purchase checklist, not a full reliability score.

FAQs

Short answers about how to read this model-year guide.

The 2018 BMW 6 Series follows the pattern of the model years either side. In 2025, 86.4% of 2,168 first MOTs on the 2018 BMW 6 Series passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 87.9%. Among 294 failed first-attempt MOT tests (test year 2025), Drive shaft joints and boots (front) appears more often than on similar cars (9.5% of those tests; 27 observed failures; about 3.4× more often than similar cars). There is no single reliability score here; this is a pre-purchase checklist built from DVSA open data, not a guarantee for any individual car.
Ranked by how often they were actually recorded, the items that most often failed a 2018 BMW 6 Series at the first attempt were Tyre condition (front) (21.2%), each as a share of the year's failed first attempts. That is what goes wrong most often on the car. The common faults table shows a different measure: faults that are unusual compared with similar cars.
Among failed first-attempt tests we highlight patterns that appear more often than on similar cars. Top example: Drive shaft joints and boots (front) (9.5% of those tests; 27 observed failures; about 3.4× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Drive shaft joints and boots (front) shows up more often than on similar cars (9.5% of those tests; 27 observed failures; about 3.4× more often than similar cars). That does not prove a design fault. Age, mileage, and how the car was used still matter. Treat it as a pre-purchase checkpoint, not a manufacturer service bulletin.
Common MOT problem areas for the 2018 BMW 6 Series include Drive shaft joints and boots (front). These are the faults that stand out compared with similar cars, not a complete list of what can go wrong on any individual car.
This page highlights MOT failure patterns for the 2018 BMW 6 Series (registration year) using UK DVSA open data for the selected test year. Patterns are compared with cars of a similar age and mileage. It is a buyer checklist from MOT defect statistics, not a full service history or manufacturer service-bulletin list.
No. MOT tests do not cover engine internals, gearboxes, or many electronic modules. Patterns here come from MOT defect statistics only and should not be read as engine or gearbox reliability scores.

About this data

How this page is built and what it can (and can't) say.

These figures come from UK MOT open data for this model year. We surface common failure patterns against similar cars, not a full reliability score, and not a pass/fail verdict on any individual vehicle.

2024 2025

What we include

UK Class 4 cars only. Normal MOT tests (not retests); first test per vehicle per calendar year; results pass, PRS, or fail.

Same-day repairs

PRS means the car failed items that were fixed at the test station and then passed the same day. We count PRS as a first-attempt fail in headline rates so same-day repairs do not hide problems.

How we compare

We compare this model year with other Class 4 cars of similar age and mileage in the same test year. This model family is left out of the peer group so the car is not measured against itself.

What this does not cover

  • MOTs do not cover engine internals, gearboxes, or many electronics; this is not a full reliability score.
  • Common faults come from MOT defect stats, not manufacturer TSBs or recalls.
  • Age and mileage matching reduces, but does not remove, differences in how cars were used and maintained.
  • If the data for a car is too thin to say anything useful, we say so rather than guess.

Contains public sector information licensed under the Open Government Licence v3.0.

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