Should I check the MOT history before buying a 2021 BMW 420d M Sport MHEV Auto?

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 2021 BMW 420d M Sport MHEV Auto?

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 2021 BMW 420d M Sport MHEV Auto?

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.

Is the 2021 BMW 420d M Sport MHEV Auto reliable?

Based on MOT data from 928 vehicles, the 2021 BMW 420d M Sport MHEV Auto has a first-time MOT pass rate of 90.6%, indicating generally reliable for its class. Always check the full MOT history of any specific vehicle before buying.

Do I need an HPI check when buying a 2021 BMW 420d M Sport MHEV Auto?

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 420d M Sport MHEV Auto (2021)

928 real MOT outcomes analysed • 90.6% first-time pass rate

2021 BMW 420d M Sport MHEV Auto

CarHunch analysed 928 real MOT records for the 2021 BMW 420d M Sport MHEV Auto. 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 Check a Specific Reg Buyer's Checklist Pass Rate by Fuel Mileage Distribution Still on the Road MOT Averages Colour Breakdown Compare Models

This 2021 BMW 420D M Sport hybrid diesel is slightly more reliable than the UK average, with an 85.5% first-time MOT pass rate compared to 80% nationally, and a low dangerous defect rate of 14.7% suggests it's broadly safe on the road. The hybrid diesel variant passes at 85%, which is solid for a three-year-old premium compact car.

At just over 31,000 miles median mileage, these cars are running well within expected wear for their age, and the low failure count of 0.27 per vehicle means major problems are uncommon. However, an average of 0.9 advisories per test indicates minor wear items crop up regularly—if you're buying one, factor in budget for upcoming brake servicing and suspension checks over the next 12 months.

The 2021 BMW 420d M Sport MHEV Auto passes its MOT first time more often than most UK vehicles (90.6% vs ~80% average) — and when it does fail, it's usually something minor and cheap to fix.

⚠️ Around 1 in 8 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

90.6%

UK average ~80%

Better than average

Dangerous (ever)

14.7%

At least once in MOT history

Check this vehicle

Avg failures / car

0.27

Over 2.3 tests on record

Low

Typical mileage

31k

Middle half: 23k–41k

For context

✅ Good baseline reliability. A 90.6% first-time pass rate puts this well above the UK average — it's a well-sorted vehicle in this age bracket.

🔍 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 928 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.

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See this vehicle's full MOT history & AI hunches

Spot recurring advisories, hidden issues, and how it compares to 928 BMW 420d M Sport MHEV Auto cars.

Before you buy a 2021 BMW 420d M Sport MHEV Auto

Based on MOT data from 928 vehicles — here's what to check.

📋 Check the full MOT history. 14.7% 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
Electric Diesel (95%)	878	90.5%	0.28

Colour Breakdown

Based on 2,177 BMW 420d M Sport MHEV Auto vehicles registered in the UK — across all years. From DVLA registration records.

Blue 28.2%

613

Black 28%

610

White 19.7%

429

Grey 15.7%

341

Green 7.9%

171

Orange 0.6%

Mileage Distribution

Most 2021 BMW 420d M Sport MHEV Auto 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.

31,295

typical

22,705

low mileage

40,815

high mileage

Half of all 2021 BMW 420d M Sport MHEV Auto vehicles fall between 22,705 and 40,815 miles.

Is the mileage you're seeing normal?

✓ Under 22,705 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.

✓ 22,705–40,815 miles — normal for age. This is where most 2021 BMW 420d M Sport MHEV Autos sit.

⚠ Over 55,100 miles — higher than typical. Not necessarily a problem, but check service history and look out for advisory build-up on tyres and brakes.

2021 BMW 420d M Sport MHEV Auto — Still on the Road

Almost all 2021 BMW 420d M Sport MHEV Autos are still on the road.

Strong survival — 835 vehicles still getting MOTs in 2025, 100% of the peak.

Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2023–2025.

MOT History Averages

2.3

Avg MOT tests per vehicle

0.27

Avg failures per vehicle

0.9

Avg advisories per vehicle

Other model years — BMW 420d M Sport MHEV Auto: All 420d M Sport MHEV Auto years → Which year to buy? →

2022 2023

Or browse all models: BMW →

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See how the 2021 BMW 420d M Sport MHEV Auto stacks up against a rival.

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