Common Problems with the
2021 BMW 5 Series (G30)

We've identified 2 known issues that can affect the 2021 BMW 5 Series (G30). None are considered critical, but they're worth knowing about before you buy.

Known Issues

Serious

Moderate

Minor

The 2021 period has 1 more issue than the BMW 5 Series (G30) average across all year periods.

All Known Issues

Coolant Expansion Tank Leak

ModerateCooling System

Hairline cracks around the expansion tank or attached fittings can cause repeated low-coolant warnings on B48 and B58 petrol cars.

Most affected: 520i, 530i, 540i

Estimated cost: £150–£350Affects: 2017–2021Often appears around: 25,000-70,000 miles

Typical symptoms

•Intermittent low-coolant warnings
•Pink residue around the tank seam
•Sweet smell after shutdown

What to inspect before you buy

✓Inspect the tank and vent hose closely under strong light
✓Check whether coolant level is stable across multiple heat cycles
✓Look for recent top-up bottles in the boot

Display Key Screen Failure

MinorElectrics & Electronics

Cars fitted with the touchscreen display key can suffer battery degradation, poor charging, or a dead screen, which is annoying rather than critical but expensive for a key.

Most affected: Higher-spec SE and M Sport models with display key option

Estimated cost: £200–£400Affects: 2017–2024Often appears around: Age-related rather than mileage-specific

Typical symptoms

•Blank or dim key screen
•Key losing charge quickly
•Intermittent comfort-access recognition

What to inspect before you buy

✓Confirm both keys are present and working
✓Check whether the display key charges properly in its cradle
✓Do not overpay for the feature if it is already failing

Buying Tips for the 2021 BMW 5 Series (G30)

✓B48/B58 petrols are generally strong, but recurring coolant top-ups deserve investigation rather than a casual seller explanation
✓Make sure every ADAS function, parking camera, and radar-based aid works; bumper knocks can turn into expensive sensor alignment jobs
✓Check run-flat tyre wear carefully because inner-edge wear on heavy M Sport cars can arrive before owners notice it
✓If it is a diesel, still verify EGR recall status and DPF health even though the G30 is better than earlier BMWs overall

2020 BMW 5 Series (G30)2022–2024 BMW 5 Series (G30)