Should I check the MOT history before buying a 2018 BMW 420?

Yes. Look for recurring advisories — slow-building issues like corrosion or brake wear patterns show up years before they become failures. A full MOT history analysis will highlight patterns that a single test result won't reveal.

What corrosion should I look for when inspecting a 2018 BMW 420?

Check brake pipes, sills, subframes, and chassis legs. Surface rust is normal at this age; structural rust is a serious problem that is expensive to fix and can fail an MOT.

How are tyres and brakes typically on a 2018 BMW 420?

Tyres and brakes are the most common advisory items on vehicles of this age. Budget for replacement if they are near the limit, and factor this into your offer price.

How many 2018 BMW 420 vehicles have had dangerous defects recorded?

28% of these vehicles have had a dangerous defect recorded. Search the registration on CarHunch — the full MOT history will show exactly what was flagged and whether it was resolved.

Is the 2018 BMW 420 reliable?

Based on MOT data from 10,491 vehicles, the 2018 BMW 420 has a first-time MOT pass rate of 89.8%, indicating generally reliable for its class. Always check the full MOT history of any specific vehicle before buying.

What are common problems with the 2018 BMW 420?

The most frequently recorded MOT issues on the 2018 BMW 420 are: Nearside Rear Tyre worn close to legal limit/worn on edge (35.5% of vehicles), Offside Rear Tyre worn close to legal limit/worn on edge (34.8% of vehicles), Offside Front Tyre worn close to legal limit/worn on edge (27.8% of vehicles). These figures are based on actual MOT test records — search a specific registration on CarHunch to see its individual history.

Do I need an HPI check when buying a 2018 BMW 420?

Yes. The MOT history will not show outstanding finance, insurance write-offs, or stolen status. An HPI check covers these areas and should be part of any used car purchase.

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BMW 420 (2018)

10,491 real MOT outcomes analysed • 89.8% first-time pass rate

2018 BMW 420

CarHunch analysed 10,491 real MOT records for the 2018 BMW 420. Real test outcomes — pass rates, defect profiles, mileage data — from verified DVLA records. Updated as new MOTs are recorded.
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AI Analysis Reliability Overview Common Issues Check a Specific Reg Buyer's Checklist Pass Rate by Fuel Mileage Distribution Still on the Road MOT Averages Colour Breakdown Compare Models

The 2018 BMW 420 passes its MOT first time in 89.8% of cases, well above the UK average of 80%, though nearly three in ten examples have recorded a dangerous defect at some point—a notably high proportion that warrants a thorough pre-purchase inspection. Petrol and diesel versions perform almost identically (90.1% and 89.5% pass rates respectively), so fuel choice won't materially affect reliability here.

These 420s average just 42,382 miles at test time, suggesting they're low-mileage examples that haven't yet accumulated significant wear, yet they're already averaging 0.67 failures per vehicle—more than would be typical for their age and distance. The 4.4 advisories per car point to niggling electrical and trim issues common to modern BMWs; before buying, get an independent diagnostic scan to check for hidden fault codes that MOT inspectors won't always catch.

The 2018 BMW 420 has a decent first-time pass rate (89.8%), but a higher-than-average share of vehicles have had serious defects recorded — the individual vehicle's history matters a lot here.

⚠️ Over 1 in 5 of these vehicles have had a dangerous MOT failure at some point — usually tyres or brakes, and often a one-off issue rather than a persistent problem. The group stats won't tell you which one you're looking at.

First-time pass

89.8%

UK average ~80%

Better than average

Dangerous (ever)

28.3%

At least once in MOT history

Check this vehicle

Avg failures / car

0.67

Over 5.7 tests on record

Moderate

Typical mileage

44k

Middle half: 34k–58k

For context

✅ Good baseline reliability. A 89.8% first-time pass rate puts this well above the UK average — it's a well-sorted vehicle in this age bracket.

🔧 Expect consumable spend. An average of 4.4 advisories per vehicle tells you wear items (tyres, brakes) get flagged regularly. Budget for them — they're not surprises.

🔍 The dangerous defect figure is real. Most are one-off tyre failures or brake issues — not structural problems. But it's exactly why checking the individual vehicle's history is essential, not optional.

These stats describe 10,491 vehicles as a group. The specific vehicle you're looking at could be the one good example or the one outlier. Run its registration to find out.

Watch for defects — worth knowing

What tends to go wrong

Across 10,491 vehicles — figures show how many had each issue flagged at least once in their MOT history.

Tyre wear 35.5%

Nearside Rear Tyre worn close to legal limit/worn on edge · Offside Rear Tyre worn close to legal limit/worn on edge · Offside Front Tyre worn close to legal limit/worn on edge · …

Budget for a full set — on a vehicle this age, tyres are expected consumables. An inspection will confirm how much is left.

Brake wear 27.3%

Rear Brake pad(s) wearing thin · Front Brake pad(s) wearing thin · Front Brake disc worn, pitted or scored, but not seriously weakened · …

Ask the seller when brakes were last serviced. If they don't know, factor in the cost.

Suspension & steering 11%

Offside Front Play in steering rack inner joint(s)

Harder to spot without a ramp — this is a good reason to book a pre-purchase inspection.

Other issues 10%

COVID-19 6 MONTH EXTENSION · Nearside Rear Child Seat fitted not allowing full inspection of adult belt · Windscreen damaged but not adversely affecting driver's view

Data covers a 3-year window centred on 2018.

See this vehicle's full MOT history & AI hunches

Spot recurring advisories, hidden issues, and how it compares to 10,491 BMW 420 cars.

Before you buy a 2018 BMW 420

Based on MOT data from 10,491 vehicles — here's what to check.

📋 Check the full MOT history. 28.3% of these vehicles have had a dangerous defect recorded - recurring advisories often signal problems years before they become failures.
Search the reg on CarHunch for the full MOT history, reliability stats and a free AI-powered analysis of that exact vehicle.
🔍 Brake pipes, sills and subframes are the key areas on a vehicle this age — structural rust is hard to spot without getting underneath. A mechanic will check all of this before you commit, and give you a concrete basis to negotiate on price. Inspection →
📄 Outstanding finance, insurance write-offs and clocking won't appear in the MOT records — a dedicated history check covers all of this. Our link gets you 20% off automatically. History Get 20% off via CarHunch

Pass Rate by Fuel Type

Fuel type	Vehicles	Pass rate	Avg failures
Diesel (52%)	5,448	89.5%	0.69
Petrol (48%)	5,043	90.1%	0.66

Colour Breakdown

Based on 66,334 BMW 420 vehicles registered in the UK — across all years. From DVLA registration records.

Black 26.1%

17,314

White 23.8%

15,781

Blue 21.5%

14,235

Grey 18.8%

12,480

Silver 6.2%

4,131

Red 2.8%

1,854

Orange 0.2%

165

Brown 0.2%

142

Beige 0.2%

140

Green 0.1%

Yellow 0%

Bronze 0%

Mileage Distribution

Most 2018 BMW 420 vehicles sit in the blue band. If the vehicle you're looking at is outside it, it's either unusually low or high mileage for its age.

44,298

typical

34,016

low mileage

57,572

high mileage

Half of all 2018 BMW 420 vehicles fall between 34,016 and 57,572 miles.

Is the mileage you're seeing normal?

✓ Under 34,016 miles — lower than most. Could be great, or could be a vehicle that rarely moved. Check test frequency and mileage progression in the MOT history.

✓ 34,016–57,572 miles — normal for age. This is where most 2018 BMW 420s sit.

⚠ Over 77,722 miles — higher than typical. Not necessarily a problem, but check service history and look out for advisory build-up on tyres and brakes.

2018 BMW 420 — Still on the Road

Almost all 2018 BMW 420s are still on the road.

Strong survival — 9,711 vehicles still getting MOTs in 2025, 96% of the peak.

Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2021–2025.

MOT History Averages

5.7

Avg MOT tests per vehicle

0.67

Avg failures per vehicle

4.4

Avg advisories per vehicle

Other model years — BMW 420: All 420 years → Which year to buy? →

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Compare with another model

See how the 2018 BMW 420 stacks up against a rival.

Watch for defects — worth knowing