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Audi · Known Issues

2000 Audi S4 Problems: 4 Known Issues

2000 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated September 2026

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Issue summary

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2000 Audi S4 has 4 documented known issues, with 3 rated critical. The most serious are Driver Airbag Inflator May Deploy Improperly (Recall 21V470 / 69CJ), 2.7T Timing Belt Service Is Mandatory - Interference Engine Destroys Itself if the Belt or Tensioner Lets Go ($1,100-$2,000 repair) and 2.7T Biturbo Turbocharger Failure from Undersized, Coking Oil Feed and Return Lines ($2,500-$7,000 repair). Across all issues with published estimates, repair costs range from $800 to $7,000. DIY maintenance guides at au7o.io.

In This Article

  • S4 Engine2
  • S4 Safety/Recalls1
  • S4 Suspension1
  • Recalls1
  • FAQ
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In This Article

  • Engine2
  • Safety/Recalls1
  • Suspension1
  • Recalls1

All 4 Known Issues

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On the 2000-2002 Audi S4, unlike every later S4, the B5's 2.7T 30V V6 uses a TIMING BELT, and it is an interference design. A snapped belt, a seized tensioner/idler, or a water pump that fails and shreds the belt results in bent valves and, in some cases, cracked pistons - a total engine rebuild. The revised service interval for the 2.7T 30V is 75,000 miles, and because every B5 S4 is now 20+ years old, the age limit (roughly six years) matters more than the mileage: tensioners, the damper, the water pump and the associated seals and O-rings are all at or past end of service life. Cars bought used with unknown belt history are the common loss case.

Common Symptoms

  • No start or sudden engine stop while driving after belt failure
  • Squeal or grinding from the front of the engine (failing idler/tensioner bearing)
  • Coolant leak from the timing cover area (water pump behind the belt)
  • Rough running and severe misfire after a belt jump

How to Fix

Replace the complete timing belt kit - belt, tensioner, idlers, damper, and the water pump - not just the belt. Budget the full front-end service; on the 2.7T this is done in "service position" with the front clip pulled forward. Typical parts-and-labor figures quoted by owners and shops run about $1,100-$1,600. If belt history cannot be documented on a purchase, treat the service as due immediately regardless of odometer reading.

Typical repair cost:$1,100 - $2,000

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High ConfidenceVerifiedReviewed Aug 2026

On the 2000-2002 Audi S4, on the B5 S4's 2.7L twin-turbo V6 (APB/AGB), the turbocharger oil feed and return lines are too small in diameter to move enough oil through the turbo bearing housings. After a hot shutdown the residual oil bakes (cokes) inside the lines, progressively restricting flow until the turbo bearings are oil-starved and fail. This is a design issue specific to the 2000-2002 2.7T as fitted to the B5 S4 (and the contemporary A6/allroad); Audi went to larger-diameter lines on the 2003+ A6/allroad, but the S4 was discontinued after 2002 so NO B5 S4 ever got the revised parts from the factory. Failure typically shows as smoke, boost loss and oil consumption, and a failed turbo can dump oil and debris downstream.

Common Symptoms

  • Blue or grey smoke from the exhaust, especially under boost or on overrun
  • Loss of boost / underboost fault
  • High oil consumption
  • Whining or siren noise from a turbo
  • Oil in the intercooler piping

How to Fix

No recall exists. When either turbo is replaced, the oil feed AND return lines on BOTH sides must be replaced (or upgraded to the larger-diameter later-spec lines) - reusing coked lines is the classic cause of a repeat failure on a brand-new turbo. Preventatively, owners replace the lines during any major service, use a full-synthetic oil on a shortened interval, and let the engine idle briefly before shutdown after hard driving. Turbos are usually done as a pair because access requires the same teardown.

Typical repair cost:$2,500 - $7,000

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On the 2000-2002 Audi S4, certain 2000-2002 S4 vehicles have a non-azide driver airbag inflator that can absorb moisture and deploy improperly, reducing occupant protection in a crash.

Common Symptoms

  • Open safety recall
  • No reliable warning before airbag deployment

How to Fix

Check the VIN with Audi or NHTSA. Audi dealers replace the driver frontal-airbag inflator with an alternative inflator free of charge under campaign 69CJ.

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On the 2000-2002 Audi S4, the B5 S4 uses a multi-link front suspension with four control arms per side, and both the rubber bushings and the integrated ball joints are known short-life items - a problem noted even on relatively fresh cars and now universal given the fleet's age. The rubber compound hardens, cracks and separates with age and heat exposure regardless of mileage, so a low-mileage garage-kept B5 is no safer a bet than a driver. The result is clunking over bumps, imprecise or wandering steering, and uneven tire wear; badly deteriorated arms are also a safety concern because the ball joints are non-serviceable and integral to the arm. CV boots are a commonly co-occurring wear item on the same cars.

Common Symptoms

  • Clunking or knocking from the front over bumps
  • Vague, wandering steering; poor straight-line tracking
  • Uneven or feathered front tire wear
  • Steering wheel shimmy
  • Play detectable at the wheel when levered

How to Fix

No recall. The accepted fix is replacing the front control arms in complete sets per side rather than chasing individual arms, followed by a four-wheel alignment - a partial repair usually means going back in shortly afterward. OEM or quality aftermarket kits are widely available; many owners choose polyurethane or Delrin bushings for longer life at the cost of some ride harshness. Because the whole assembly is being disturbed, inspect tie rods, sway bar end links and CV boots at the same time.

Typical repair cost:$800 - $2,000

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NHTSA Recalls1 recall

AIR BAGS:FRONTAL:DRIVER SIDE:INFLATOR MODULE

Volkswagen Group of America, Inc. (Volkswagen) is recalling certain 2000-2001 Audi TT Coupe, TT Roadster, 2000-2002 A4, and S4 vehicles equipped with Non-Azide Driver Air Bag Inflators (NADI) that do not contain phase stabilized ammonium nitrate (PSAN) propellant. Due to a manufacturing issue, the NADI inflators may absorb moisture, possibly causing the air bag to deploy improperly in the event of a crash.

Campaign #21V47000023/06/2021

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Frequently Asked Questions

What are the most common Audi S4 problems?

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2000 Audi S4 has 4 documented issues. The most frequently reported are: Driver Airbag Inflator May Deploy Improperly (Recall 21V470 / 69CJ), 2.7T Timing Belt Service Is Mandatory - Interference Engine Destroys Itself if the Belt or Tensioner Lets Go, 2.7T Biturbo Turbocharger Failure from Undersized, Coking Oil Feed and Return Lines. Of these, 3 are rated critical and should be addressed promptly.

Is the Audi S4 reliable?

The 2000 Audi S4 has 4 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 3 issues are rated critical: Driver Airbag Inflator May Deploy Improperly (Recall 21V470 / 69CJ) and 2.7T Timing Belt Service Is Mandatory - Interference Engine Destroys Itself if the Belt or Tensioner Lets Go and 2.7T Biturbo Turbocharger Failure from Undersized, Coking Oil Feed and Return Lines. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Audi S4 problems?

Repair costs for known Audi S4 issues range from $800 to $7,000, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 2000-2002 Audi S4 Driver Airbag Inflator May Deploy Improperly (Recall 21V470 / 69CJ)?

Certain 2000-2002 S4 vehicles have a non-azide driver airbag inflator that can absorb moisture and deploy improperly, reducing occupant protection in a crash. Severity: high.

What is the 2000-2002 Audi S4 2.7T Timing Belt Service Is Mandatory - Interference Engine Destroys Itself if the Belt or Tensioner Lets Go?

Unlike every later S4, the B5's 2.7T 30V V6 uses a TIMING BELT, and it is an interference design. A snapped belt, a seized tensioner/idler, or a water pump that fails and shreds the belt results in bent valves and, in some cases, cracked pistons - a total engine rebuild. The revi… Repairs typically run $1,100-$2,000. Severity: high.

Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

Data compiled from NHTSA recalls, manufacturer TSBs, automotive forums, and AI-assisted research. No aggregated owner-report counts available for this vehicle yet.

FAQ

What is the 2000-2002 Audi S4 2.7T Biturbo Turbocharger Failure from Undersized, Coking Oil Feed and Return Lines?

On the B5 S4's 2.7L twin-turbo V6 (APB/AGB), the turbocharger oil feed and return lines are too small in diameter to move enough oil through the turbo bearing housings. After a hot shutdown the residual oil bakes (cokes) inside the lines, progressively restricting flow until the… Repairs typically run $2,500-$7,000. Severity: high.

What is the 2000-2002 Audi S4 B5 Front Multi-Link Control Arm Bushings and Ball Joints Wear Out, Causing Clunks and Wandering Steering?

The B5 S4 uses a multi-link front suspension with four control arms per side, and both the rubber bushings and the integrated ball joints are known short-life items - a problem noted even on relatively fresh cars and now universal given the fleet's age. The rubber compound harden… Repairs typically run $800-$2,000. Severity: medium.