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Audi · Mid-Size · 2003–2006 Custom Search

Audi S4 B6

Weaknesses, engine ratings and buying advice

★★★★★
1.0 / 5.0 · Based on 1 engine variants · How we rate

Body Variants

The Audi S4 B6 is available as Sedan and Avant and Convertible — choose your body type for specific insurance data:

Generations

Engine Overview

The Audi S4 B6 is available with one engine variant at 344 hp.

S4 · Petrol· 344 PS
2003 2006

High-revving V8 naturally aspirated with direct injection, fitted in S4 B6/B7, RS4 B7, S5 B8 and R8. Timing chain sits on the gearbox side — repair requires engine removal. Oil change intervals of max. 10,000 km are mandatory. Short-trip use massively accelerates wear.

  • !! Timing chain: tensioners and guide rails — THE main problem from 80,000 km

    Chain tensioners and guide rails on the BBK wear prematurely, often from 60,000 km. Chain skips teeth → engine damage. Complete engine removal required; gearbox must be separated. Costs: 2,600–7,500 €.

    Symptoms: Metallic rattling on cold start, progressively louder ticking at operating temperature, engine warning light, sudden power loss
    2,600–7,500 $
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  • !! Alusil cylinder bore wears — elevated oil consumption to engine failure from 120,000 km

    The BBK uses Alusil-coated aluminium cylinders (not Nikasil). With sulphur-containing oil or long intervals the bore surface is damaged. Oil consumption rises to up to 4 L/1,000 km; result: piston seizure. Engine block replacement ~10,000 €.

    Symptoms: Rapidly increasing oil consumption, blue smoke, falling compression, borescope reveals bore damage
    3,000–15,000 $
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  • !! Camshaft adjusters generate fault codes — limp home from 70,000 km

    Camshaft adjusters on the BBK wear and generate camshaft deviation fault codes. Vehicle goes into limp-home mode. Adjuster replacement possible without engine removal; tensioners/rails require engine removal.

    Symptoms: Rattling on start, engine warning light, limp-home mode, reduced engine output, rough idle
    500–3,000 $
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+ 5 more engine weaknesses + vehicle weaknesses

Vehicle Weaknesses

WeaknessCost
!Control arms and ball joints wear

The front control arms wear accelerated by the S4's high weight. Ball joint play is a typical MOT failure point. Full replacement often required at 200,000 km.

Symptoms: Knocking and banging over surface irregularities, unsettled handling, steering flutter
from 150,000 km
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 Medium
NHTSA Owner Complaints
Below average
108 complaints · 2003–2006
  1. 01 Lighting
    59
  2. 02 Engine & Cooling
    16
  3. 03 Airbags
    12 ⚠ 2
  4. 04 Electrical
    11 ⚠ 1
  5. 05 Powertrain
    9

Top Reported Issues

⚠ Lighting (59 complaints)
⚠ Engine & Cooling (16 complaints)
⚠ Airbags (12 complaints)
Source: NHTSA (nhtsa.gov) · 2026-03

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Known Problems and Issues +

A total of 13 weaknesses have been documented for the Audi S4 B6 (2003–2006) — 8 engine-related and 5 vehicle-related. One problem engine: BBK (4.2L V8 FSI). Typical issues affect Suspension, Rust, Brakes, Electronics.

What to watch out for with the Audi S4? See the detailed listing of all engine and vehicle weaknesses in the sections above.

Frequently Asked Questions

What problems and weaknesses does the Audi S4 B6 have? +
The Audi S4 B6 has 8 known engine weaknesses and 5 vehicle weaknesses.
What should I look for when buying a used Audi S4 B6? +
faq.watch_a_avoid
Which engine is recommended? +
None of the available engines are rated 'Good Choice'. Stay away! The most fun to drive is the BBK (4.2L V8 FSI). Problem engine: BBK (4.2L V8 FSI) — stay away!
Which Audi S4 B6 engine is the most fun? +
The {code} ({displacement}) offers the most driving fun in the Audi S4 B6 — rated: "Legendary!". {description} Audi puts a V8 in the S4 for the first time — and nails it. High-revving to 8,250 rpm, with a manual it is a mechanical experience. The B6 sounds rawer and less refined than the later B7. Less polished, more visceral. The beginning of a short, glorious V8 era.
Is the Audi S4 B6 worth buying used? +
Caution is advised with the Audi S4 B6 — 1 of 1 engine variants are rated 'Stay Away!'. The engine choice is crucial.
What horsepower variants are available for the Audi S4 B6? +
The Audi S4 B6 is available with engine variants from 344 to 344 hp. Petrol: BBK (4.2L V8 FSI).

Last updated: February 2026 · All information without guarantee