Used car guide

2021 BMW Z4: common problems and what to check

What gets flagged at MOT on 2021 BMW Z4s, from 1,069 tests in 2025, plus known faults and what to look at before you buy one.

1,069MOT tests in 2025
91%pass first time (all 2021 cars: 87%)
5,500typical miles a year
2.4×the usual rate for nail or damage in a tyre

What stands out

Parts flagged at MOT more often on 2021 BMW Z4s than on all cars registered in 2021.

  • Nail or damage in a tyre2.4× usual
    BMW Z4
    5% All 2021 cars
    2.1%

    Failed outright at MOT: 0%, against 0% of all 2021 cars. The rest were advisories or minor defects.

    Rough price £70–£150 our estimate

    At the viewing: Check the tread on all four tyres, including the inside edges. Uneven wear can point to tracking or suspension problems.

By area

The share of 2021 BMW Z4 MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Tyres
    25% of testsRough price £70–£150

    At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

  • Lights and electrics
    2% of testsRough price £10–£80

    At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

  • Wipers, windscreen and mirrors
    2% of testsRough price £15–£250

    At the viewing: Check for chips in the driver's view, and test the wipers and washers.

  • Brakes
    1% of testsRough price £150–£350

    At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

  • Suspension
    1% of testsRough price £120–£400

    At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

Looking at a BMW Z4?

Check the actual car: its own MOT history, mileage and what to ask the seller. Free, no sign-up.

Other years

YearMOT testsMost flagged
2022934Tyres 23%
20201,532Tyres 25%
20192,009Tyres 26%
20161,235Tyres 25%
20151,589Tyres 25%
20141,916Tyres 28%
20131,571Tyres 29%
20121,838Tyres 26%
20111,965Tyres 25%
20101,954Tyres 25%
20092,420Tyres 24%
20081,749Suspension 33%
20073,099Brakes 33%
20062,880Brakes 39%
20051,967Brakes 41%
20042,898Brakes 40%
20032,354Brakes 39%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 2021 BMW Z4s registered in 2021. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score