EngineHigh
N20/N26 timing chain and guide wear (earlier builds most affected).
BMW 3 Series vs Audi A4 · reliability compared
Both scores come from the documented faults we hold for each model · severity weighted, then priced at UK independent-garage rates so you can see which car carries the bigger risk.
The short answer
On the faults we hold, the BMW 3 Series scores 4.3 against 3.5 for the Audi A4 · fewer or less severe documented problems. The Audi A4 carries the higher worst-case repair bill.
BMW 3 Series
2012–2018
4.3/ 10
Buy with caution- Documented faults
- 8
- Critical / high
- 0 / 3
- Medium / low
- 4 / 1
- Priciest job
- £900–£2,600
- Worst-case total
- £10,900
Weak spots · Engine, Cooling, Steering, Electrical
Audi A4
2009–2016
3.5/ 10
Buy with caution- Documented faults
- 8
- Critical / high
- 1 / 2
- Medium / low
- 4 / 1
- Priciest job
- £900–£3,200
- Worst-case total
- £12,200
Weak spots · Engine, Intake, Cooling, Suspension
The faults that decide it
CoolingHigh
Electric water pump and thermostat failure.
EngineHigh
Sudden loss of power, loud popping noise under boost, and a 'Drivetrain Malfunction' warning due to the factory plastic charge pipe splitting.
EngineHigh
2.0T TFSI excessive oil consumption from worn piston rings (early builds).
EngineCritical
Timing chain tensioner failure — can cause catastrophic damage if it lets go.
TransmissionHigh
Jerky shifting, hesitation pulling away, or stalling due to S tronic (DL501) mechatronic unit failure.
Scores are computed from the documented faults in our library for each model · they reflect reported patterns, not the condition of a specific car.
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