BMW 420 (2017)
Running costs, reliability data, and common problems from 25,467 real MOT tests.
Annual Cost
£1,487
£124/month
MOT Pass Rate
90%
Excellent
Road Tax
£195
Flat rate/year
Insurance
Grp 18-32
1995cc Diesel
Great Choice
90% pass rate, £1487/year to run. 8 points above average.
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Annual Running Costs
~48 mpg
Flat rate (post-2017)
Low estimate due to excellent reliability
Based on 7,400 miles/year (UK average), current fuel prices, and repair likelihood from MOT data. Insurance not included.
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Reliability Verdict
Excellent reliability. Very few MOT failures. That's 8 points above the national average of 82%.
At 9 years old, 90% of BMW 420s from 2017 passed their MOT first time in 2026. That's based on 25,467 tests across the UK. The average mileage at this age is 64,302 miles.
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How Does It Compare?
Mileage Analysis
64,302
Average miles
66,600
Expected for age
The average 2017 BMW 420 has 64,302 miles on the clock, which is in line with the expected 66,600 miles for a 9-year-old car, suggesting normal everyday use.
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Best Year to Buy?
The most reliable year is the 2021 model with a 94% MOT pass rate, while the 2013 model has the lowest at 85%. The 2017 sits between the two at 90%.
BMW 420 by Year
Similar Cars to Consider
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About the 2017 BMW 420
The 2017 BMW 420 is a premium with a 1995cc diesel engine. 25,467 of these vehicles were MOT tested in 2026, making it one of the most commonly tested cars on UK roads. Among all cars from 2017, the average MOT pass rate is 87%, and this model beats that benchmark.
With an average of 64,302 miles at 9 years old, BMW 420 owners drive about as much as the UK average.
2017 BMW 420 Fuel Costs
The 1995cc diesel engine offers a reasonable balance between performance and economy. Expect around 48 mpg in mixed driving, which works out to roughly £1,037 per year at current diesel prices of 148p per litre (based on 7,400 miles per year). Diesel cars of this age should have their DPF (diesel particulate filter) checked, as replacements can be costly.
What does it cost to own a 2017 BMW 420?
Total estimated annual running cost is £1,487 (£124/month), broken down as £1037 fuel, £195 road tax, £55 MOT, and £200 predicted repairs. The low repair estimate reflects the excellent 90% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.
BMW 420 Reliability Trend
Newer BMW 420s show better MOT pass rates than older ones, with an average improvement of 4 percentage points.
Buying a Used 2017 BMW 420
At 9 years old, this is a solid used buy if you find one with good service history. Depreciation has levelled off, so you won't lose much more value. Focus on condition over mileage. If you're flexible on year, the 2021 model has the highest pass rate at 94%. With 25,467 MOT tests in our data, there's strong statistical confidence in these figures.
Common Issues to Watch For
Based on the 2017 BMW 420's fuel type, age, and engine size, these are the most likely problem areas to check.
DPF (Diesel Particulate Filter)
Watch outShort journeys clog the DPF. Replacement costs £1,000-£2,500. Check the DPF warning light and ask about driving patterns.
Turbo Wear
Watch outDiesel turbos work harder and wear faster. Listen for whining noises and check for oil leaks around the turbo housing.
AdBlue System
Medium riskPost-2015 diesels use AdBlue for emissions. Sensor failures and tank heater issues are common. Budget £200-£500 for repairs.
EGR Valve
Watch outExhaust Gas Recirculation valves clog with carbon deposits, causing rough running and poor economy. Cleaning costs £150-£300, replacement £300-£600.
Suspension Wear
Medium riskShock absorbers, springs, and anti-roll bar links typically need attention around this age. Listen for clunks over bumps and check for uneven tyre wear.
Service History
Low riskAlways request a full service history. Regular servicing is the single best indicator of how well a car has been maintained, regardless of mileage.
Running Costs Compared
How the 2017 BMW 420 stacks up against similar cars for annual running costs, insurance, and tax.
| Car | Pass Rate | Fuel/yr | Tax/yr | Insurance | Total/yr |
|---|---|---|---|---|---|
| BMW 420(2017) | 90% | £1037 | £195 | Grp 18-32 | £1487 |
| VOLKSWAGEN GOLF(2017) | 91% | £905 | £190 | Grp 12-25 | £1350-£137 |
| FORD FOCUS(2019) | 89% | £905 | £190 | Grp 12-25 | £1500+£13 |
| AUDI A3(2015) | 88% | £905 | £135 | Grp 12-25 | £1445-£42 |
| FORD TRANSIT(2017) | 81% | £1037 | £190 | Grp 18-32 | £1632+£145 |
Estimates based on 7,400 miles/year, current fuel prices, and MOT data. Insurance groups are indicative. Actual costs vary by driver, location, and usage.
Related Bmw Models
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