Back to search

2006 AUDI S4

4.2L V8•AWD•AUTOMATIC•gas
5-Year Cost of Ownership
$82,171 maintenance + known platform issues
~$16,434/yr · 1,370¢/mile equivalent · $48,412 maintenance + $9,759 expected platform issues
Compare this engine
vs
3.0L Turbo V6
Common Problems & Known Issues

The B7 S4 with the 4.2L V8 is a stellar performer when maintained, but the timing chain guide and carbon buildup issues can turn expensive fast. Budget for preventive maintenance or walk away.

Timing Chain Guide and Tensioner Failure

Common · high severity
Typical onset: 80,000-120,000 mi
Symptoms: rattling on cold start that fades after warmup, metallic noise from front of engine, check engine light with cam/crank correlation codes, catastrophic engine failure if guides break
Fix: Engine-out job requiring front-end removal, all guides, tensioners, and chains replaced. 20-25 labor hours at a competent indie shop. Do NOT delay once rattling starts.
Estimated cost: $4,500-7,000

Carbon Buildup on Intake Valves

Common · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: rough idle and misfires, loss of power especially under load, poor fuel economy, multiple misfire codes
Fix: Direct injection means no fuel washing valves. Walnut blasting required every 60-80k miles. 4-6 labor hours, intake manifold removal.
Estimated cost: $600-1,200

Front Control Arm Bushings

Common · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: clunking over bumps, steering wander and vague turn-in, uneven tire wear, vibration through steering wheel
Fix: OEM arms are not rebuildable; requires full control arm replacement on both sides. 3-4 hours labor, alignment required after.
Estimated cost: $800-1,400

Oil Consumption from Piston Ring Land Failure

Occasional · high severity
Typical onset: 90,000-150,000 mi
Symptoms: burning 1+ quart every 1,000 miles, blue smoke on startup or deceleration, fouled spark plugs, eventually leads to complete engine failure
Fix: Known FSI engine defect. Requires full engine rebuild or short block replacement. 30-40 labor hours. Some had extended warranty coverage; check service history.
Estimated cost: $8,000-15,000

Transmission Cooler and Mount Failures

Occasional · medium severity
Typical onset: 80,000-130,000 mi
Symptoms: transmission fluid leaking from cooler lines, harsh shifts or slipping, clunking when shifting from park to drive, vibration at idle in gear
Fix: Cooler lines crack at fittings; mounts collapse from V8 torque. Cooler is 2-3 hours, mounts are 1-2 hours each. Do mounts when doing clutch or major service.
Estimated cost: $400-1,000

Supercharger Bypass Valve and Diverter Valve Leaks

Occasional · low severity
Typical onset: 70,000-120,000 mi
Symptoms: hissing sound under hood during acceleration, slight loss of boost pressure and power, rough idle occasionally, check engine light for boost pressure codes
Fix: Diaphragms tear in valves over time. Replacements are straightforward, 1-2 hours labor. Use OEM or quality aftermarket; cheap parts fail quickly.
Estimated cost: $300-600

Window Regulator Failure

Common · low severity
Symptoms: slow or jerky window operation, window drops into door and won't raise, grinding or clicking noise from door
Fix: Plastic gears strip in regulators. 1.5-2 hours per door, door panel removal required. Common on all four windows eventually.
Estimated cost: $350-550
Owner tips
  • Listen for cold-start rattles on test drive; timing chain noise is a dealbreaker unless severely discounted
  • Budget $1,500/year for carbon cleaning and preventive maintenance if buying high-mileage
  • Check service records for oil consumption complaints or engine work; ring land failures often start subtly
  • Use only 5W-40 full synthetic and keep oil topped off; low oil accelerates timing chain wear
  • Test all windows, check for control arm play during inspection; these nickel-and-dime items add up fast
Buy only with documented timing chain service and clean compression test; otherwise you're gambling with a $6k repair bill at any moment.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
593 jobs across 17 categories
Building an app?
Free API access to all this data — 50 requests/day, no card required.
Get an API key →
Run a shop?
Manage repairs, estimates, and customers with ShopBase — $249/mo, all features included. Built by the same team.
Try ShopBase →