IsItAGoodCar

Common Problems with the
2018 Mazda 3 (BM/BN)

We've identified 4 known issues that can affect the 2018 Mazda 3 (BM/BN). 1 of these are serious faults that could be expensive to repair.

4
Known Issues
1
Serious
1
Moderate
2
Minor

The 2018 period has 3 more issues than the Mazda 3 (BM/BN) average across all year periods.

All Known Issues

2.2 SkyActiv-D DPF and Oil Dilution

SeriousEngine

Short-trip town use causes frequent interrupted DPF regenerations on the 2.2 diesel, allowing diesel to dilute the engine oil. This can accelerate timing-chain, turbo and bottom-end wear. The problem is severe enough to warrant regular oil-level checks between services.

Most affected: 2.2 SkyActiv-D

Estimated cost: £300–£4,000Affects: 2013–2019Often appears around: 40,000–80,000 miles

Typical symptoms

  • •Rising oil level on dipstick
  • •DPF warning light
  • •Limp mode after town use

What to inspect before you buy

  • ✓Check the dipstick level carefully; oil above the maximum mark is a red flag
  • ✓Ask what kind of journeys the car typically does
  • ✓Look for invoices for DPF cleaning or turbo work

Brake Disc Warping

ModerateBrakes

The front brake discs on BM/BN Mazda3s are prone to developing run-out and thickness variation, causing a judder through the steering wheel and brake pedal during braking. This is more common on cars used heavily in town with frequent low-speed stops.

Estimated cost: £150–£350 per axleAffects: 2013–2019Often appears around: 30,000–60,000 miles

Typical symptoms

  • •Vibration through steering wheel under braking
  • •Pulsing brake pedal
  • •Uneven pad wear

What to inspect before you buy

  • ✓Test brake feel from moderate speed
  • ✓Inspect front discs for scoring or a visible lip
  • ✓Check MOT history for brake advisories

Folding Mirror Motor Failure

MinorElectrics & Electronics

The plastic gears in the mirror motor strip, causing the mirrors to get stuck or make a clicking noise.

Estimated cost: £150–£300 per mirrorAffects: 2014–2018

Typical symptoms

  • •Mirror won't fold/unfold
  • •Grinding noise

What to inspect before you buy

  • ✓Fold and unfold the mirrors several times using the door switch

12V Battery Premature Failure

MinorElectrics & Electronics

The Mazda3 BM/BN is known for draining its 12V battery faster than expected, particularly on models with the i-stop (start-stop) system. Owners frequently report needing replacement batteries after just two to three years.

Estimated cost: £100–£180Affects: 2013–2019

Typical symptoms

  • •Slow cranking on cold mornings
  • •Stop/start system not engaging
  • •Battery warning light

What to inspect before you buy

  • ✓Check the battery age and condition
  • ✓Verify the stop/start system activates during the test drive
  • ✓Ask when the battery was last replaced

Buying Tips for the 2018 Mazda 3 (BM/BN)

  • ✓Prefer the 2.0 SkyActiv-G petrol over any diesel.
  • ✓Check the infotainment screen for spider-web cracking (delamination).
  • ✓Test the folding mirrors multiple times.
2014–2017 Mazda 3 (BM/BN)2019 Mazda 3 (BM/BN)

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Other Mazda 3 (BM/BN) Year Periods

20132014–201720182019

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