Audi RS4
The CFSA is Audi's farewell gift from the naturally aspirated V8 — 8,250 rpm rated speed, 450 PS without a turbo. The character is the opposite of a BiTurbo: the engine demands revs and rewards with a sound no production family car offers any more. Double throttle body in the intake: soft down low, sharp up top. Direct injection (FSI) is the structural weakness: without fuel washing over the intake valves, their backs coke up from blow-by oil vapour. Walnut blasting every 50,000–70,000 km is mandatory. The variable intake manifold with flaps tends to rattle from oil deposits — bolts can come loose and fall into the engine. Timing chain fundamentally robust, needs clean oil and short change intervals.
RS4 B8 — NA V8 in a wagon, the last of its kind
450 hp naturally aspirated V8 at 8,250 rpm in a wagon. After the B7, the second and last generation with a high-revving V8. Heavier and less raw than the B7, more liveable in return. The auto fits better than expected — shift speed makes the loss of the manual bearable.
Engine Weaknesses 9
CFSA uses simplex chains on the gearbox side. Although more robust than the BBK predecessor, tensioners and guides are wear items. Engine removal mandatory for a full repair. Significantly more durable with regular short oil change intervals.
Symptoms: Rattle on cold start, timing chain noise at low revs, engine warning light
The CFSA revs to 8,250 rpm as a high-revving naturally-aspirated engine. Con rod bearings are under extreme stress. Neglected oil changes or poor-quality oil risk bearing wear. Preventive replacement at 80,000–100,000 km is discussed.
Symptoms: Knocking from the engine at operating temperature, increasingly loud rumbling at high revs, oil pressure drop
Four camshaft adjusters on the CFSA are more heavily stressed by high-rev operation up to 8,250 rpm than a normal V8. Oil quality and short change intervals are critical for longevity.
Symptoms: Rattle on start, camshaft fault codes, limp mode
The flaps in the variable intake manifold stick due to oil deposits from crankcase ventilation and begin to rattle. In the worst case screws or flap fragments come loose and are ingested by the engine — piston and valve damage can result.
Symptoms: Rattling or clattering from the intake area at idle and low revs, rough idle, individual cylinder misfires.
FSI deposits on intake valves documented from as early as 32,000 km, especially severe with urban use. Walnut blasting costs 600–900 € for RS4/RS5. Regular cleaning every 40,000–60,000 km recommended.
Symptoms: Power loss (up to 40 hp), rough idle, poor throttle response at low revs
RS4/RS5 with CFSA shows elevated oil consumption due to high revs and spirited use. Valve stem seals and piston rings wear. 1–2 L/1,000 km during spirited driving is normal.
Symptoms: Oil level drops noticeably, slight blue smoke after full-throttle sections, oil consumption above 1 L/1,000 km
CFSA water pump is heavily stressed in RS4/RS5 high-performance use. Failure after 100,000–140,000 km. Replace thermostat at the same time. Tight engine bay in the RS4 B8 means higher labour costs.
Symptoms: Coolant level drops, temperature fluctuations, coolant smell after driving
The FSI high-pressure pump in the CFSA can fail after 80,000–100,000 km. In the RS4/RS5 with high-performance demands this is particularly critical. Expensive replacement due to cramped engine bay.
Symptoms: Starting problems, severe power loss, hesitation under load, fuel smell
8 ignition coils in the CFSA are particularly prone to failure due to high-rev use. Motorsport-oriented use increases wear. Complete coil replacement 300–700 €.
Symptoms: Misfires, engine warning light with misfire code, hesitation on acceleration
Vehicle Weaknesses 9
The CVT Multitronic (type 0AW) is known for frequent failures through 2011. Juddering, imprecise shifting or complete failure from around 150,000 km. Expensive reconditioning or replacement required.
Water ingress through the rear lights can short-circuit the wiring harness and cause expensive electrical damage. A weak starter battery is a recurring issue since many systems draw power continuously.
The complex front axle shows wear at higher mileages in suspension components, control arm bushings and springs. Brake hoses regularly appear on repair lists.
On TFSI petrol engines the coolant water pump is a known wear point between 50,000 and 100,000 km. Loose hose clamps can also lead to coolant loss.
The S tronic dual-clutch gearbox is sensitive to frequent city driving and towing. Clutch judder and shifting problems occur. Regular gearbox oil changes extend service life.
Springs break through corrosion on the powder coating after stone chip damage. Front axle springs particularly affected. A broken spring can damage the tyre.
Rear brake calipers seize, particularly after winter periods. Defective seals allow water ingress and pistons corrode.
The MMI system frequently fails due to overvoltage damage during battery replacement or moisture damage. Control unit or interface box defective.
Loose heat shields on the exhaust system are a frequent source of noise. Simple repair by reshaping or renewing the fixings.