IsItAGoodCar
Reliability Guide

Common Problems with the
2021 MINI Convertible (F57)

The second life-cycle update (LCI-2) came in 2021: restyled front and rear bumpers, LED headlights and Union Jack tail lamps made standard, a new steering wheel and ambient lighting inside, and a petrol particulate filter that cost the Cooper S's B48 about 10hp while cleaning up emissions. This is the last specification of the Born-built Convertible before production ended in 2024, and the most polished F57 to buy.

What changed for 2021

  • •Union Jack rear lighting and LED headlamps standardised
  • •Petrol particulate filters fitted, trimming Cooper S power by roughly 10hp
  • •Revised interior trim, steering wheel and MINI OS infotainment

Common MOT watch-outs

  • !Run-flat tyre wear and mismatched sets on cars changing wheels
  • !Front suspension bushes and top mounts under UK wheels
  • !Brake disc corrosion on short-hop cars in winter salt
  • !Tailgate and roof electronics moisture in the drain channels
4
Known Issues
1
Serious
3
Moderate
0
Minor

All Known Issues

BDC (Body Domain Controller) Water Damage

SeriousElectrics & Electronics

Water ingress from blocked drains or A-pillar seals can damage the BDC module, leading to total electrical failure.

Est. Repair Cost: £500–£1,500
Warning Signs:

Interior electronics failing, Lights flickering, Roof operation issues, No-start

What to Inspect:
  • Check for dampness in the passenger footwell
  • Ensure sunroof/roof drains are clear
  • Look for corrosion on BDC plugs
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Upper Engine Mount Failure

ModerateEngine

The same hydraulic upper mount issue seen on the F56 hatch creates extra vibration and drivetrain movement.

Est. Repair Cost: £250–£450
Warning Signs:

Idle vibration, Knock when moving off, Visible leaking mount

What to Inspect:
  • Inspect mount for cracks and fluid loss
  • Watch engine movement when blipping the throttle
  • Ask if the updated mount has been fitted
Verified by IsItAGoodCar Research Team

Roof Position Sensor / Drain Issues

ModerateBodywork & Rust

The electric soft top is reliable overall, but blocked drains or failing position sensors can interrupt operation and lead to damp trim.

Est. Repair Cost: £150–£700
Warning Signs:

Roof stops mid-cycle, Roof warning light, Wet rear trims or boot lining

What to Inspect:
  • Run the hood multiple times
  • Inspect drains and roof seals
  • Check for signs of mildew or recently dried carpets
Verified by IsItAGoodCar Research Team

Front Suspension Bush Wear

ModerateSuspension & Chassis

Heavy wheels and UK potholes wear front bushes and drop links, causing the familiar MINI knock from the front axle.

Est. Repair Cost: £200–£400
Warning Signs:

Knocking at low speed, Tyre shoulder wear, Slight steering tug under braking

What to Inspect:
  • Inspect front arm bushes and drop links
  • Check alignment and tyre wear
  • Drive over rough roads with the roof up and down
Verified by IsItAGoodCar Research Team

Buying Tips for 2021 MINI Convertible (F57)

  • Pay up for the 2021-on car for the tech and tail lamps alone - resale follows
  • Check the roof functions fully; late cars should cycle fast and silence-clean
2019–20202022–2024
Check a 2021 MINI Convertible (F57) by Registration