Audi S5
4.2-litre FSI V8 with 354 PS. Intake valve carbon build-up from direct injection documented from 40,000–60,000 km; walnut blasting recommended. Timing chain on gearbox side — replacement requires engine removal (very costly). Watch oil consumption and cold-start rattling as early warning signs of chain issues.
Supercharged V6 in a coupé — the whine is addictive
Same 3.0 TFSI as the S4, but in better-looking clothes. The supercharger whine becomes addictive — according to owners, it's the secret reason they bought the car. With ZF auto, one of the most reliable S-Audis. As a coupé, a more cohesive package than the sedan.
Engine Weaknesses 12
Like all 4.2 FSI V8 engines, the upper timing chain guide rail breaks. In the S5 Coupe with its tighter bodywork equally labour-intensive as in the S4. Engine removal mandatory. Cost: 2,600–7,500 €.
Symptoms: Rattle on cold start, progressive rattle at operating temperature, limp mode, engine warning light
Four camshaft adjusters on the CGKD wear due to low oil or long change intervals. Rattling, fault codes and limp mode. Spirited S5 use increases wear.
Symptoms: Rattle on start, engine warning light, limp mode, power loss
The guide rails of the gearbox-side timing chain tend to fracture. Fragments collect in the oil pan. Chain replacement requires full engine removal — an extremely costly repair.
Symptoms: Rattling on cold start (1–3 seconds), metallic clicking at low rpm, engine warning light with camshaft correlation fault.
FSI direct injection causes severe carbon deposits on intake valves. Significant deposits on the S5 from 40,000–60,000 km. Main complaint on older models.
Symptoms: Power loss, rough idle, poor throttle response, increased consumption
Valve stem seals and piston rings wear in the 4.2 FSI V8 with increasing mileage. More pronounced in the S5 due to spirited driving. 1–2 L/1,000 km in old age typical.
Symptoms: Oil level drops, blue smoke on pull-away or acceleration, oil consumption above 1 L/1,000 km
The clutch on the S5 V8 is reported to be the main weakness alongside the engine itself. Significantly higher wear during spirited driving. Full clutch replacement 800–2,000 €.
Symptoms: Diminishing clutch performance, clutch slipping, increased fuel consumption, shifting problems
The S5 4.2 V8 water pump fails after 100,000 km. Higher labour cost in the relatively tight A5 8T engine bay. Coolant loss and risk of overheating.
Symptoms: Coolant level drops, temperature gauge rises, coolant smell, overheating warning
Massive carbon deposits on the intake valves from lack of fuel wash in direct injection. EGR gases and blow-by bake onto the valves. Walnut blasting every 60,000–80,000 km recommended.
Symptoms: Power loss, rough running especially cold, cold-start misfires, worse fuel economy.
The V8 camshaft phasers can malfunction with insufficient oil pressure or oil quality. Control of intake and exhaust camshafts loses precision — power loss and fault codes follow.
Symptoms: Rough idle after cold start, P-codes for slow camshaft adjustment (bank 1/2), sporadic power loss.
At higher mileages, piston rings and valve stem seals tend to wear. Oil enters the combustion chamber. Blue smoke and dropping oil levels are typical early signs — engine rebuild is very costly.
Symptoms: Blue smoke from the exhaust especially after idling, dropping oil level, oil smell after extended driving.
8 ignition coils in the V8 fail repeatedly. Spirited use of the S5 increases stress. Individual coil is cheap, but replacing all 8 at once costs 300–700 €.
Symptoms: Misfires, hesitation, engine warning light with misfire code, rough running
Timing chain cover gasket and camshaft shaft seals develop leaks. Oil at front of engine. Engine removal for complete resealing. Access more difficult in the S5 Coupe.
Symptoms: Oil puddles under vehicle, oil film on front of engine, oil smell after driving
Vehicle Weaknesses 8
The CVT Multitronic (0AW) tends to catastrophic failures around 100,000 km: juddering when pulling away, extreme rpm fluctuations and loss of reverse gear. Without regular gearbox oil changes, complete failure is likely.
A5 and Q5 models from 2008–2012 with a defective passenger airbag inflator. On deployment, uncontrolled gas pressure can release metal fragments.
Dampers and control arms wear noticeably from around 80,000 km, especially on Sport and S line suspension. A full control arm set costs €2,000–3,000; individual rear dampers around €1,000.
At the transitions between underbody sealant and paint, rust bubbles form on sills and wing bases. Dirt and moisture collect behind underbody covers.
The S tronic dual-clutch gearbox shows premature clutch wear in stop-and-go traffic and when towing. Juddering when pulling away and harsh gearshifts, often fixable by software update.
TÜV inspection reports flag brake hoses on the A5 8T twice as often as the class average. From around 10 years of age rubber hoses become porous.
The window regulator mechanism frequently breaks, especially on the Coupe. The window regulator module must then be replaced completely.
The AC compressor can fail at higher mileages, especially if the AC has not been used for extended periods.