According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2002 Audi S8 has 1 documented issue, with 1 rated critical. The most serious is D2 4.2 V8 Timing Belt and Tensioner Service (Interference Engine) ($1,000-$2,500 repair). Across all issues with published estimates, repair costs range from $1,000 to $2,500. DIY maintenance guides at au7o.io.
On the 2001-2003 Audi S8 4.2L 40V V8 (AYS), the first-generation D2 S8 uses the 4.2L 40-valve V8, an interference engine driven by a timing belt (intake cams) plus chains (exhaust cams). The belt is a maintenance-critical, age-and-mileage-limited item: Audi specifies replacement around 105k miles, but many specialists recommend shorter intervals (or every ~6 years) because failure is catastrophic — a snapped belt lets valves and pistons collide. Associated tensioners, rollers, and the water pump are commonly replaced together. On these older cars the chain tensioners on the exhaust side can also wear and rattle. This is the single most important service to verify on any D2 S8 purchase.
Replace the timing belt as a complete kit — belt, tensioner, idler/guide rollers, and water pump — at or before Audi's interval (and by age regardless of mileage). Use genuine/OE-quality components and set cam/crank timing precisely with the correct locking tools; this is a front-of-engine ('service position') job. Inspect the exhaust-side chain tensioners while in there. Always confirm timing-belt history (with receipts) before buying a D2 S8; if unknown, do it immediately.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
Engine Timing Belt
Cross-refTB297
Fitment confirmed against the ShowMeTheParts catalog for this vehicle's year and engine.
According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2002 Audi S8 has 1 documented issue. The documented issue is: D2 4.2 V8 Timing Belt and Tensioner Service (Interference Engine). Of these, 1 is rated critical and should be addressed promptly.
Is the Audi S8 reliable?
The 2002 Audi S8 has 1 known issue compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 1 issue is rated critical: D2 4.2 V8 Timing Belt and Tensioner Service (Interference Engine). 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 S8 problems?
Repair costs for known Audi S8 issues range from $1,000 to $2,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, D2 4.2 V8 Timing Belt and Tensioner Service (Interference Engine), typically costs $1,000-$2,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 2001-2003 Audi S8 D2 4.2 V8 Timing Belt and Tensioner Service (Interference Engine)?
The first-generation D2 S8 uses the 4.2L 40-valve V8, an interference engine driven by a timing belt (intake cams) plus chains (exhaust cams). The belt is a maintenance-critical, age-and-mileage-limited item: Audi specifies replacement around 105k miles, but many specialists reco… Repairs typically run $1,000-$2,500. 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.
