4.2 V8 40V (ARS/ASG/AQJ/ANK/BAS/BAT/BBK) vs 2.5 TFSI I5
Side-by-side reliability comparison
Higher reliability score
2.5 TFSI I5
BUY
83/100
+23 points over 4.2 V8 40V (ARS/ASG/AQJ/ANK/BAS/BAT/BBK)
0
/ 100
CAUTION
4.2 V8 40V (ARS/ASG/AQJ/ANK/BAS/BAT/BBK)
Audi
0
/ 100
BUY
2.5 TFSI I5
Audi
Specifications
4.2 V8 40V (ARS/ASG/AQJ/ANK/BAS/BAT/BBK)
2.5 TFSI I5
Brand
Audi
Audi
Verdict
CAUTION
BUY
Reliability
60
83
Years
1999--2009
2009--present
Displacement
4163 cc
2480 cc
Layout
V8
I5
Type
Petrol Na
Petrol Turbo
Power
299--344 hp
340--400 hp
Known Issues
1
2
Total Risk Cost
€1,380--€3,220
€700--€1,600
Character
4.2 V8 40V (ARS/ASG/AQJ/ANK/BAS/BAT/BBK)
"The 40-valve port-injection 4.2 V8 of the S4 B6/B7, S6 C5 and A6 4.2. Glorious sound, but the plastic guides and tensioners of the rear-mounted timing chains break up with age and heat - an engine-out job, and if the chain jumps a tooth the valves meet the pistons. Listen to a cold start and look for proof of the chain job."
2.5 TFSI I5
"Legendary 5-cyl. 9x Engine of the Year. Forged internals. Surprisingly reliable."
Issues Comparison
4.2 V8 40V (ARS/ASG/AQJ/ANK/BAS/BAT/BBK) 1
◆ CRITICAL
Plastic timing-chain guides and tensioner break up - engine-out repair
2.5 TFSI I5 2
○ MINOR
Wastegate rattle (2015-2018 production)
○ MINOR
Carbon buildup (DI engine)