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 13
The 7-speed S-tronic DL501 is prone to judder when pulling away and when shifting, especially under load or at low temperatures. The cause is usually a worn dual-clutch pack or a faulty mechatronic valve block.
The S5 8T has an elaborate four-link front axle made of aluminium. Control arm bushings and ball joints wear prematurely under spirited driving and motorway use. Replacing all four control arms per axle involves significant cost.
On the optional sport differential the end caps of the driveshafts do not seal permanently. Heat build-up from the exhaust system creates internal pressure that overcomes the adhesive joint. Audi TPI 2025572/1 exists.
Hydraulic hoses for the electric hood become brittle and crack. Hydraulic fluid runs into the boot or onto the exhaust heat shield. Primarily affects early hoses (production up to end of 2010).
Early S5 8T models (pre-facelift 2012) developed rust blisters at the sill-to-wheel arch liner transition and on wing edges. Audi frequently covered repairs under goodwill. Paint quality improved after the facelift.
The optional CDC chassis uses electronically controlled Sachs dampers. After approximately 150,000 km, leaks or reduced control response are reported. Drive Select between Comfort and Sport makes little noticeable difference.
The MMI 3G/3G+ is prone to complete failure caused by overvoltage, moisture in the Bluetooth control unit or a defective radio module. A MOST-bus interruption takes down the entire system.
The thermostat on the 3.0 TFSI supercharged V6 (CAKA) fails and stops opening the main coolant circuit. Despite coolant temperatures reaching 110°C no fault codes are stored. Replacement requires removing the supercharger.
On S5 8T models with the Bang & Olufsen sound system, blocked drains or a leaking rear screen washer can cause water damage to the amplifier in the boot. Audi provides a free protective cover.
Dirt accumulates between the plastic underbody panels and wears through the corrosion protection. Rust forms at mounting points and weld seams. Annual removal and cleaning is considered essential.
A characteristic whine or squeal occurs at full lock. The cause is excessive hydraulic pressure at maximum steering travel or wear in the power steering pump. Incorrect fluid level can make the problem worse.
The S5 sport brake system (340 mm front) requires specific pads and discs. Under sporty driving pads can be due after 30,000–40,000 km. Only one side has a wear sensor.
The Milano leather on the side bolsters of the S5 sport seats is considered too thin. Friction when getting in and out causes noticeable wear on the outer bolsters from around 80,000 km.