Performance by cohort

3 year bands · 77,391 tests

Pass rate climbs 13.1 points across the cohorts — newer Z4 examples clear the test more reliably than the early cars.

Pre-2018 cohort 64,025

Pass

81.2%

Fail

15.2%

PRS

3.1%

Avg mileage at test

76,995 mi

2018–2020 cohort 9,983

Pass

92.5%

Fail

6.3%

PRS

0.9%

Avg mileage at test

24,724 mi

2021+ cohort 3,383

Pass

94.3%

Fail

4.8%

PRS

0.5%

Avg mileage at test

18,545 mi

Cohort = vehicle's first-registration year band. Same model, different generations of build.

Generations on file · 3

BMW Z4 · UK market

Photos: Wikimedia Commons · CC BY-SA / CC BY / public domain.

The picture

BMW Z4: mixed MOT record across 41,916 tests

The BMW Z models are a line of roadsters manufactured by German automaker BMW. The Z stands for Zukunft, and has been produced in four different series with six generations consisting of roadster, coupé, sports car, and concept variants.

MOT data from 41,916 tests puts this car on a 79.6% first-time pass rate, roughly in line with the UK fleet average. Average mileage at test is 69,693 miles. The most common fail item is cracked or discoloured windscreen, followed by brake pipe damaged or excessively corroded.

Buyers weighing up a used Z4 should treat the failure breakdown as a pre-purchase checklist. The pass rate is reasonable, but the gap between first attempt and a clean sheet narrows with age and mileage.

ABI Insurance Group

Group 36–46

A high-group car — insurance costs will be significantly above average. Lower groups cost less to insure; UK fleet average is around Group 22.

Source: ABI Group Rating Panel · administered by Thatcham Research · groups cover standard variants; performance trims may sit higher. Browse all insurance groups →

36–46

out of 50

Compare quotes →

Top ten reasons for rejection.

Filter failures:

Hide wear items to see the model's real defects.

01

Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view

1,289 occurrences · 1.7% of tests
02

A tyre cords visible or damaged

1,151 occurrences · 1.5% of tests
03

Brake pipe damaged or excessively corroded

1,090 occurrences · 1.4% of tests
04

A rear registration plate lamp or light source missing or inoperative in the case of multiple lamps or light sources

1,068 occurrences · 1.4% of tests
05

Headlamp reflector or lens slightly defective

981 occurrences · 1.3% of tests
06

Tyre tread depth not in accordance with the requirements

923 occurrences · 1.2% of tests
07

A spring or spring component fractured or seriously weakened

760 occurrences · 1.0% of tests
08

A tyre seriously damaged

690 occurrences · 0.9% of tests
09

Engine MIL illuminated indicating a malfunction

684 occurrences · 0.9% of tests
10

Wiper blade missing or obviously not clearing the windscreen

670 occurrences · 0.9% of tests

Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.

Worst-case fix budget · top 4 failures

£118–£300

If every one of this Z4's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →

Try the calculator

Build your own retest budget.

Year-band analysis

Best year to buy. Worst to avoid.

First-time MOT pass rate split by registration band. A 13.1-point gap between bands means the year you buy BMW Z4 has a real effect on what turns up at the garage.

Best band to buy

94.3%

2021+ registration

the 2021-on band climbs to 94.3% — a 13.1-point improvement. Tests in this band average 18,545 miles — roughly 58K miles fewer on the clock than the older band. Failures here are mostly wear items: has ply or cords exposed, has a cut in excess of the… — the structural issues that drag down older examples don't appear in the top-10 for this band. Post-2020 examples are early in their MOT life and generally show the cleanest records.

Band to be cautious about

81.2%

Pre-2018 registration

On the older band (pre-2018), the data shows a 81.2% pass rate against a fleet average of 94.3% on the newer band. The main culprits logged at test: damaged but not adversely affecting driver's view, excessively corroded, and inoperative in the case of multiple lamps…. Average mileage on test for this band is 76,995 miles — high-mileage wear items are a recurring theme.

Best band to buy: 2021+ (94.3% first-time pass). Worst band to avoid: pre-2018 (81.2% pass). That's a 13.1-point spread across 64,025 older tests and 3,383 newer ones — year of build makes a material difference on this model.

Year-spread leaderboard →

Tools that pre-empt a retest.

Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.

Item 01 · Amazon UK

Digital tyre-tread depth gauge

Five quid for a gauge beats £150 for a retest. UK MOT minimum is 1.6mm — most testers fail anything below 2mm to be safe.

Search Amazon UK

Item 02 · Amazon UK

H7 / W21W bulb pack

A spare-bulb kit lives in the boot. Test morning is not the time to find your stop-lamp's gone.

Search Amazon UK

Item 03 · Amazon UK

Headlight restoration kit

Yellowed lenses fail the light-output test. A restoration kit lifts the haze in an afternoon for £20.

Search Amazon UK

My Motor World · affiliate

Parts & supplies for this fix

Affiliate links — small commission, no extra cost to you.

Summit

Summit ADRG-640 BMW Replacement Stick-On Tinted Mirror Glass LHS

£10.99

View at My Motor World →

Summit

Summit ADRG-904 BMW Replacement Stick-On Tinted Mirror Glass RHS

£10.99

View at My Motor World →

Summit

Summit ADRG-905 BMW Replacement Stick-On Tinted Mirror Glass LHS

£10.99

View at My Motor World →

Draper Expert

Draper Expert Oil Filter Socket for Audi, BMW, Mercedes-Benz, Porsche and VW

£18.69

View at My Motor World →

Click Mechanic · affiliate

Book a mobile mechanic

Affiliate links — small commission, no extra cost to you.

Mobile mechanic · UK-wide

Book a mechanic at your door.

Fixed-price quotes upfront. No garage needed. Click Mechanic sends a vetted local mechanic to you — home, work, or roadside.

Get a quote →

Recall history

14 UK recalls on record.

The Z4 has 14 official UK vehicle recalls covering defect details, remedies, and affected build dates.

See all recalls

Buying or keeping a Z4?

Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.

If you own a Z4 and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.