Used buying checklist
BMW 420 reliability, common problems and used buying checks
A used BMW 420 looks better than average for reliability in UK MOT data: 12.1% of 71,832 tests failed, compared with 18.7% across all indexed models. A good example should have a clean MOT history for suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels.
It can be, if the exact car has a clean history for suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels.
Start with suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels, then compare the car's mileage and recall record below.
Sources used: DVSA MOT tests (Apr 2026); vehicle recalls (Apr 2026); MOT fault wording (May 2025). MOT data does not capture every reliability issue, especially intermittent engine, gearbox or infotainment faults that do not appear during the test.
- 12.1% MOT failure rate
- Median tested mileage 53,727 miles
- 8,693 failed MOT tests analysed
Suspension and steering is the clearest area to check
Suspension and steering is the clearest named problem area in this model's MOT history (5.0 MOT notes per 100 tests). Example MOT phrases from this area include ball joint excessively worn, play in steering rack inner joint(s), and ball joint has excessive play.
Example MOT phrases to search in the car's history:
- ball joint excessively worn
- Play in steering rack inner joint(s)
- ball joint has excessive play
- across an axle
- damaged but not adversely affecting driver's view
- Items removed from drivers view prior to test
- provides insufficient washer liquid
- of an obligatory external mirror significantly affected by an obstruction
- Nail in tyre
- Wheel/tyre protruding beyond wheel arch
Focus on suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels
The model's recorded failure rate is 12.1%, -6.6 percentage points compared with the average across all models. Use the seller questions below to check whether repeat MOT notes have actually been repaired.
- MOT tests analysed71,832 tests
- Median tested mileage53,727 miles
- Failed MOT tests8,693
Should you buy a used BMW 420?
87.9% of the MOT tests we analysed for this model passed. The model's recorded failure rate is 12.1%, -6.6 percentage points compared with the average across all models. This is a buying brief for the exact car in front of you: clean repeat history matters more than badge reputation.
- Repeat unresolved MOT notes for suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels
- suspension and steering appearing across more than one MOT
- Any dangerous MOT failure on the exact car, especially if the same area appears again later
- A seller who cannot explain MOT wording such as "ball joint excessively worn"
It can be, if the exact car has a clean history for suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels.
Start with suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels, then compare the car's mileage and recall record below.
Suspension and steering is the clearest named problem area in the MOT history (5.0 MOT notes per 100 tests). These counts are issue notes, not failure rates, because a single MOT can list several faults.
Past 100k miles on the BMW 420, MOT records most often point to suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels.
The MOT failure rate rises from 8.7% at 0-3 years to 22.4% at 10-15 years. Compare the car with the nearest age range before treating a fault as normal wear or a warning sign. The average MOT failure rate across all models in the same dataset is 18.7%.
Start with suspension and steering, windscreen, wipers, and mirrors, tyres and wheels, and lights and electrical. The checklist on this page explains why each area is being recommended, what to inspect, and what to ask the seller.
No relevant recall notices are listed in this report, but recall completion is tied to the exact vehicle, so the seller should still be able to prove recall status.
What should I check first?
Start with suspension and steering, windscreen, wipers, and mirrors, tyres and wheels, and lights and electrical. The checklist on this page explains why each area is being recommended, what to inspect, and what to ask the seller. Each item shows whether it comes from MOT results, recall notices, or a standard used-car check.
-
Suspension and steering Seen in MOT results
Suspension and steering is one of the most common MOT problem areas for this model (5.0 MOT notes per 100 tests).
What to check: Listen for knocks, check uneven tyre wear, and inspect steering play.
-
Windscreen, wipers, and mirrors Seen in MOT results
Windscreen, wipers, and mirrors is one of the most common MOT problem areas for this model (4.5 MOT notes per 100 tests).
What to check: Check windscreen damage, wiper operation, washers, mirrors, and demisting.
-
Tyres and wheels Seen in MOT results
Tyres and wheels is one of the most common MOT problem areas for this model (2.3 MOT notes per 100 tests).
What to check: Check tyre age, tread depth, sidewall damage, wheel condition, and alignment wear.
-
Lights and electrical Seen in MOT results
Lights and electrical is one of the most common MOT problem areas for this model (1.2 MOT notes per 100 tests).
What to check: Check every lamp, warning light, horn, battery condition, and dashboard messages.
-
Emissions, engine, and exhaust Seen in MOT results
Emissions, engine, and exhaust is one of the most common MOT problem areas for this model (0.6 MOT notes per 100 tests).
What to check: Check warning lights, smoke, exhaust leaks, recent emissions failures, and service history.
-
Corrosion and structure Seen in MOT results
Corrosion and structure is one of the most common MOT problem areas for this model (0.4 MOT notes per 100 tests).
What to check: Inspect sills, subframes, mounting points, arches, and underside corrosion advisories.
What changes with mileage?
Past 100k miles on the BMW 420, MOT records most often point to suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels.
Common MOT problem areas
Common faults: what usually fails on this model?
Suspension and steering is the clearest named problem area in the MOT history (5.0 MOT notes per 100 tests). These counts are issue notes, not failure rates, because a single MOT can list several faults.
Mileage and age checks
Mileage changes: what starts showing up after high mileage?
Past 100k miles on the BMW 420, MOT records most often point to suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels. On lower-mileage cars, the most common named areas are windscreen, wipers, and mirrors, tyres and wheels, and suspension and steering.
| Mileage range | Tests | Vehicles | Failure rate (vs all models) | Median mileage |
|---|---|---|---|---|
| 0-50k | 32,180 | 27,685 | 9.5%-1.4 percentage points vs all models | 33,930 miles |
| 50-100k | 32,336 | 27,029 | 13.7%-7.0 percentage points vs all models | 68,582 miles |
| 100-150k | 6,402 | 5,170 | 17.0%-9.2 percentage points vs all models | 113,744 miles |
| 150-200k | 566 | 474 | 17.0%-10.3 percentage points vs all models | 161,183 miles |
| 200k+ | 63 | 49 | 19.1%-7.5 percentage points vs all models | 212,335 miles |
Problem areas by mileage
Past 100k miles on the BMW 420, MOT records most often point to suspension and steering, windscreen, wipers, and mirrors, and tyres and wheels.
| Mileage range | Car areas most often recorded | Specific MOT defect examples |
|---|---|---|
| 0-50k |
|
|
| 50-100k |
|
|
| 100-150k |
|
|
| 150-200k |
|
|
| 200k+ |
|
|
Fair comparisons: is this problem normal for its age?
The MOT failure rate rises from 8.7% at 0-3 years to 22.4% at 10-15 years. Compare the car with the nearest age range before treating a fault as normal wear or a warning sign. The average MOT failure rate across all models in the same dataset is 18.7%. The highest failure rate by age is 22.4% for 10-15 years cars, based on 67 tests.
| Age range | Tests | Vehicles | Failure rate (vs all models) | Median age |
|---|---|---|---|---|
| 0-3 years 2023–2026 reg. |
2,356 | 2,137 | 8.7%+0.2 percentage points vs all models | 3.0 years |
| 3-6 years 2020–2023 reg. |
28,917 | 24,976 | 10.5%-0.0 percentage points vs all models | 5.0 years |
| 6-10 years 2016–2020 reg. |
40,492 | 34,082 | 13.4%-3.2 percentage points vs all models | 7.6 years |
| 10-15 years 2011–2016 reg. |
67 | 51 | 22.4%-1.2 percentage points vs all models | 10.0 years |
Recall records and data freshness
Recall context: are there safety notices to know about?
No relevant recall notices are listed in this report, but recall completion is tied to the exact vehicle, so the seller should still be able to prove recall status.
| No relevant recall notices are listed here. Recall completion is still vehicle-specific, so check the exact car with the manufacturer or DVSA. |
Related searches
Common ways people look up the BMW 420. Each link runs the search and lands on the relevant section of this report.
Related reliability guides
See where this model sits against other BMW reports by MOT failure rate and common problem area.
Compare high-confidence model reports across all makes.
Use the fleet mileage baseline before checking this model's own mileage table.
Compare this model's age pattern with the wider MOT baseline.
Sources used: DVSA MOT tests (Apr 2026); vehicle recalls (Apr 2026); MOT fault wording (May 2025). These are patterns from many MOT tests and recall notices. They help you decide what to inspect and what to ask; they do not certify the condition of one specific car.