Audi S5
Supercharged V6 with 245 kW in the S4/S5 B8. Proven drivetrain with linear power delivery. Supercharger belt and water pump are known service items.
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 15
The intercooler integrated into the Eaton supercharger can develop leaks from thermal stress. Coolant enters the combustion chamber and can cause a hydrolock with total engine damage.
Symptoms: Coolant loss without visible external leak, misfires on cylinder 3, white exhaust smoke, power loss.
Rare but catastrophic: if the high-pressure pump fails, metal swarf is distributed throughout the entire fuel system. All lines, injectors and the tank must be flushed or replaced.
Symptoms: Engine will no longer start, engine warning light with fault code 'rail pressure too low', rough running, sudden power loss.
Hydraulic chain tensioners lose oil pressure overnight. On cold start the chain rattles for 1–3 seconds until pressure builds. Persistent rattling indicates a stretched chain or defective tensioners.
Symptoms: Metallic rattling on cold start (1–3 seconds), disappears once warm. With advanced wear also persistent rattling and engine warning light.
Particularly models from 2010–2012 have water pumps with plastic impellers that wear prematurely. Coolant loss and overheating can follow. Replacement requires removal of the supercharger.
Symptoms: Coolant warning, falling coolant level, coolant puddle under the vehicle, rising temperature gauge.
The drive shaft bearing on the Roots supercharger wears at high mileages. Play in the drive shaft is detectable by hand. A complete supercharger replacement is usually necessary.
Symptoms: Mid-range whistling or grinding in sync with engine rpm, metallic noise from the supercharger, increasingly louder.
The upper chain tensioners lose oil pressure at standstill; the timing chain rattles for 1–2 seconds on cold start. With ongoing symptoms, guide rail damage and in the worst case chain jump threatens.
Symptoms: Metallic rattling immediately after cold start, fades after 1–2 seconds. With advanced wear, permanent chain noise.
The 3.0 TFSI CAKA uses an Alusil cylinder bore. When the coating wears or is damaged, oil consumption rises progressively. A defective crankcase ventilation makes the problem worse.
Symptoms: Oil consumption above 0.5 L/1,000 km, blue exhaust smoke under load, oil smell in the cabin.
The 3.0 TFSI S4/S5 shows failures of the coolant pump and thermostat at higher mileage. Thermostat faults lead to incorrect operating temperature; pump failures carry overheating risk.
Symptoms: Temperature fluctuations on the cockpit display, coolant loss, engine reaches operating temperature too late or overheats.
The front bearing of the Eaton supercharger (nose bearing) can wear at high mileage and cause whistling noises. In extreme cases, bearing failure leads to supercharger damage.
Symptoms: Whistling or whining from the supercharger area, especially at low rpm or at idle, getting louder at higher rpm.
On CGW engines (CGWA/CGWB/CGXB) blanking screws were fitted instead of check valves (part no. 06E 103 271 A) in the oil passage. Oil drains into the sump; chain rattles earlier than normal on start.
Symptoms: Loud chain rattling on cold start that develops faster than normal, oil pressure loss at standstill.
The PCV membrane tears at 60,000–80,000 km, creating excessive vacuum in the crankcase. Oil is drawn into the intake system. Its position under the supercharger makes repair expensive.
Symptoms: Rough running, power loss, engine will not rev beyond 4,000 rpm, increased oil consumption, white smoke.
Direct injection without port spray leads to carbon deposits on the intake valves from around 70,000 km. Walnut blasting is needed to restore full power.
Symptoms: Cold-start misfires, hesitant throttle response, worse fuel pick-up, increased fuel consumption.
The Eaton supercharger drive belt must be changed every 60,000 km according to Audi (internally revised from 90,000 km). A broken belt causes boost loss and supercharger damage.
Symptoms: Whistling or squealing from the engine bay, power loss at higher rpm; rarely: engine warning light.
As a direct-injection engine the 3.0 TFSI does not wet the intake valves with fuel, so oil mist from the crankcase breather deposits as oil carbon. Results in power loss and jerking.
Symptoms: Jerking at part throttle, starting problems on cold engine, power loss, rough idle.
Ignition coils and spark plugs on the 3.0 TFSI wear at 60,000–80,000 km. Mixed misfires and engine judder follow. Regular replacement prevents catalyst-damaging misfires.
Symptoms: Engine judder, rough running under load, engine warning light (P0300–P0306), noticeable power reduction.
Vehicle Weaknesses 12
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.
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.