Is the 2018 BMW 420 reliable?

Excellent reliability. Very few MOT failures. 91% of BMW 420s from 2018 passed their MOT first time in 2026, based on 22,374 tests. That's 9 points above the national average of 82%.

How much does a 2018 BMW 420 cost to run?

Estimated annual running cost is £1,487 (£124/month), including £1037 fuel, £195 road tax, £55 MOT, and £200 predicted repairs.

What is the MOT pass rate for a 2018 BMW 420?

The 2018 BMW 420 has a 91% MOT pass rate based on 22,374 tests in 2026. This ranks 268 out of 649 cars from 2018.

Which year BMW 420 is most reliable?

The 2021 BMW 420 has the highest MOT pass rate at 94%. The least reliable year is 2013 at 85%.

What is the average mileage for a 2018 BMW 420?

The average mileage for a 2018 BMW 420 is 51,167 miles, which is in line with the expected 59,200 miles for a 8-year-old car, suggesting normal everyday use.

BMW 420 (2018)

Running costs, reliability data, and common problems from 22,374 real MOT tests.

Annual Cost

£1,487

£124/month

MOT Pass Rate

91%

Excellent

Road Tax

£195

Flat rate/year

Insurance

Grp 18-32

1995cc Diesel

Great Choice

91% pass rate, £1487/year to run. 9 points above average.

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Diesel1995cc8 years old22,374 tests51k miles avg

Annual Running Costs

Fuel (Diesel, 1995cc)

~48 mpg

£1,037

Road Tax

Flat rate (post-2017)

£195

MOT Test

£55

Predicted Repairs

Low estimate due to excellent reliability

£200

Total per year£1,487

Per month£124/mo

Per week£29/wk

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

91% MOT pass rate(Excellent)

0%National avg: 82%100%

Excellent reliability. Very few MOT failures. That's 9 points above the national average of 82%.

At 8 years old, 91% of BMW 420s from 2018 passed their MOT first time in 2026. That's based on 22,374 tests across the UK. The average mileage at this age is 51,167 miles.

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How Does It Compare?

Rank among 2018 cars268th of 649(top 41%)

Rank among BMW models548th of 1,564(top 35%)

vs national average+9%(82% avg)

vs 2018 cars average+2%(89% avg)

vs BMW average+3%(88% avg)

Mileage Analysis

51,167

Average miles

59,200

Expected for age

The average 2018 BMW 420 has 51,167 miles on the clock, which is in line with the expected 59,200 miles for a 8-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 2018 sits between the two at 91%.

BMW 420 by Year

Year	Pass Rate	Tests	Avg Mileage
2021	94%	730	28,172 mi
2020	92%	6,832	32,973 mi
2019	90%	16,835	41,885 mi
2018	91%	22,374	51,167 mi
2017	90%	25,467	64,302 mi
2016	89%	25,224	75,338 mi
2015	88%	23,559	82,955 mi
2014	86%	18,990	89,334 mi
2013	85%	1,309	99,720 mi

Similar Cars to Consider

VOLKSWAGEN GOLF

2017 · 1598cc Diesel

£1,350/year

91%

same

FORD FOCUS

2019 · 1499cc Diesel

£1,500/year

89%

-2%

FORD TRANSIT

2017 · 1995cc Diesel

£1,632/year

81%

-10%

VOLKSWAGEN POLO

2018 · 1598cc Diesel

£1,500/year

84%

-7%

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About the 2018 BMW 420

The 2018 BMW 420 is a premium with a 1995cc diesel engine. 22,374 of these vehicles were MOT tested in 2026, making it one of the most commonly tested cars on UK roads. Among all cars from 2018, the average MOT pass rate is 89%, and this model beats that benchmark.

With an average of 51,167 miles at 8 years old, BMW 420 owners drive about as much as the UK average.

2018 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 2018 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 91% 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 2018 BMW 420

At 8 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 22,374 MOT tests in our data, there's strong statistical confidence in these figures.

Common Issues to Watch For

Based on the 2018 BMW 420's fuel type, age, and engine size, these are the most likely problem areas to check.

DPF (Diesel Particulate Filter)

Watch out

Short journeys clog the DPF. Replacement costs £1,000-£2,500. Check the DPF warning light and ask about driving patterns.

Turbo Wear

Watch out

Diesel turbos work harder and wear faster. Listen for whining noises and check for oil leaks around the turbo housing.

AdBlue System

Medium risk

Post-2015 diesels use AdBlue for emissions. Sensor failures and tank heater issues are common. Budget £200-£500 for repairs.

EGR Valve

Watch out

Exhaust Gas Recirculation valves clog with carbon deposits, causing rough running and poor economy. Cleaning costs £150-£300, replacement £300-£600.

Suspension Wear

Medium risk

Shock 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 risk

Always 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 2018 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(2018)	91%	£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
FORD TRANSIT(2017)	81%	£1037	£190	Grp 18-32	£1632+£145
VOLKSWAGEN POLO(2018)	84%	£905	£190	Grp 12-25	£1500+£13

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.