4.0 TDI V8 vs 2.5 TFSI I5

Side-by-side reliability comparison

Higher reliability score
2.5 TFSI I5 BUY 83/100
+31 points over 4.0 TDI V8
0 / 100
CAUTION 4.0 TDI V8 Audi
0 / 100
BUY 2.5 TFSI I5 Audi

Specifications

4.0 TDI V8
2.5 TFSI I5
Brand
Audi
Audi
Verdict
CAUTION
BUY
Reliability
52
83
Years
2003--2012
2009--present
Displacement
4134 cc
2480 cc
Layout
V8
I5
Type
Diesel
Petrol Turbo
Power
326--385 hp
340--400 hp
Known Issues
2
2
Total Risk Cost
€3,500--€10,000
€700--€1,600

Character

4.0 TDI V8

"D3 A8, Q7. V8 diesel — enormous torque. Complex. Timing chain. 8 injectors = expensive. DPF. Linked to Dieselgate (CDSB). Specialist only. Parts costs astronomical."

2.5 TFSI I5

"Legendary 5-cyl. 9x Engine of the Year. Forged internals. Surprisingly reliable."

Issues Comparison

4.0 TDI V8 2

◆ CRITICAL
Timing chain complexity €2,000--€6,000 80,000 km--150,000 km
▲ HIGH
Injector failure (8 injectors) €1,500--€4,000 100,000 km--200,000 km

2.5 TFSI I5 2

○ MINOR
Wastegate rattle (2015-2018 production) €300--€800 20,000 km--80,000 km
○ MINOR
Carbon buildup (DI engine) €400--€800 60,000 km--120,000 km

Models

4.0 TDI V8 3

Q7 4L 2007--2012 A8 D3 2005--2010 A8 D4 2010--2017

2.5 TFSI I5 5

Ducato 250/290 2011--present TT 8J 2009--2014 Q3 8U 2013--2018 A3 8Y 2022--present TT RS 2.5 TFSI 8S 2016--2023 Coupe
Full 4.0 TDI V8 Report Full 2.5 TFSI I5 Report