Audi A4 B9 (8W) (2015 – 2025)

Reliability score : 8.4/10

The Audi A4 B9 (Type 8W) is based on the MLB Evo platform, marking a major qualitative leap compared to the B8 generation. Lighter, more rigid, and technologically advanced (with the introduction of the Virtual Cockpit), it has established itself as one of the benchmarks in the premium family sedan segment. The mid-cycle facelift (Phase 2) in late 2019 brought mild hybridization (12V and 48V MHEV), the removal of the MMI rotary controller in favor of a 100% touch screen, and an aesthetic redesign. Although this report focuses on gasoline engines (TFSI) which have regained popularity, the diesel range (TDI) remains essential in the European used car market. Overall, the B9 is a very well-designed car, free from the chronic flaws of the B8 (notably the excessive oil consumption of older TFSI

✅ Strengths

Interior finish and assembly quality (segment benchmark)
Reliability of EA888 gasoline engines (B8 oil consumption issues completely resolved)
Sound insulation and ride comfort (especially with acoustic glazing)
Ergonomics of the MMI system and Virtual Cockpit
Efficiency of the Quattro transmission (Ultra or Torsen depending on version)

⚠️ Weaknesses

Fragile thermostat housing/water pump on 4-cylinder gasoline engines
Risk of engine failure on V6 gasoline engines (S4/RS4) from before mid-2018 (rocker arms)
High maintenance cost at official Audi dealerships
Capricious AdBlue system on TDI engines
Firm suspension on S line trims (without adaptive damping)

🎯 Verdict

The Audi A4 B9 is an excellent used car choice, especially with a gasoline engine (TFSI). Audi has corrected past errors: the 2.0 TFSI 4-cylinders are now very robust, with the exception of the water pump, which should be considered a wear part. The interior ages remarkably well. However, be careful with S4 and RS4 sports versions from before July 2018: the design flaw of the EA839 V6 rocker arms is a financial sword of Damocles. Prioritize a 2.0 TFSI model (40 or 45 TFSI) post-2019 (facelift) with a clear service history, especially for the S-tronic gearbox.

Common issues

Fuite de la pompe à eau (thermostat intégré) Medium

🔧 60 000 – 120 000 km

💶 400 – 800 €

Vérifier régulièrement le niveau de liquide de refroidissement et l'absence de traces.

Encrassement des soupapes d'admission (calamine) Medium

🔧 80 000 – 150 000 km

💶 300 – 600 €

Une conduite dynamique et des nettoyants spécifiques peuvent aider à limiter l'accumulation.

Défaillance de la vanne PCV (reniflard) Medium

🔧 80 000 – 140 000 km

💶 200 – 400 €

Attention à la consommation d'huile excessive ou au ralenti instable, signes potentiels.

Problèmes de mécatronique sur boîte S-Tronic (DSG) High

🔧 100 000 – 180 000 km

💶 1 500 – 3 000 €

Faire vidanger la boîte S-Tronic scrupuleusement selon les préconisations du constructeur.

Estimated maintenance costs

Oil change	£90 – 160
Timing chain	£900 – 1 800
Clutch	£900 – 1 600
Complete brakes	£350 – 700
Estimated annual budget	£700 – 1 300

Indicative estimates (independent garage, UK market). Prices vary by region and year.