The most commonly reported issues on the 2009 Audi S5 include oil consumption, timing-chain tensioner wear, cooling-system leaks, carbon buildup from the direct-injection V8, and various electrical and transmission-related problems.
As a late-2000s luxury performance car, the 2009 S5 carries a powerful V8, all-wheel drive, and sophisticated electronics that can show wear with age and mileage. This article examines the problems owners and technicians most frequently cite, along with practical guidance on diagnosis, maintenance, and budgeting for repairs.
Powertrain and engine concerns
The following items are the primary engine and drivetrain risk areas reported by owners and service providers for the 2009 S5. They can affect performance, reliability, and cost of ownership.
Key trouble spots
- Timing chain tensioner and guide wear: The chain-driven 4.2-liter V8 can develop tensioner or guide wear, leading to chain noise on start-up or idle and, in rare cases, timing issues if left unaddressed. Many owners consider preventative replacement or inspection as a proactive measure at higher mileages.
- Oil consumption and leaks: The 4.2 FSI V8 can exhibit higher-than-ideal oil consumption and/or external oil leaks from gaskets, valve covers, or seals. Regularly checking oil level and service history is important, especially with higher-mileage cars.
- Direct-injection related carbon buildup: The 4.2-liter direct-injected engine can accumulate carbon on intake valves, potentially causing rough idle, reduced performance, or misfires. Cleaning (often via walnut blasting) may be needed if buildup is significant.
- Cooling-system wear and leaks: Components such as the expansion tank, water pump, thermostat housing, and radiator hoses can develop leaks, potentially leading to overheating if not addressed promptly.
- Ignition and fuel-system concerns: Misfires or rough running can stem from worn spark plugs, ignition coils, or fuel injectors. Electrical wiring around these components can also contribute to fault codes and rough performance.
Effective maintenance—consistent oil changes with the appropriate synthetic oil, monitoring for oil usage, timely cooling-system work, and code-based diagnosis—helps mitigate these issues.
Electrical and electronics
Electrical and infotainment systems are integral to the S5 experience, but aging components and wiring can cause faults that are noticeable but often repairable with parts or software updates.
Typical electrical shortcomings
- Instrument cluster, MMI, and display glitches: Aging electronics can produce flickering displays, intermittent information, or software-related quirks that may require updates or module replacements.
- Steering and chassis electronics: EPS (electronic power steering) components or sensors can exhibit intermittent faults, leading to warning lights or changes in steering feel.
- Door and interior electronics: Window regulators, seat memory and heating controls, and related actuators can wear and fail over time, sometimes requiring regulator replacement or switch reprogramming.
Routine diagnostics with an automotive scan tool can identify fault codes and guide repairs. Battery health and alternator performance also influence electrical reliability on aging cars.
Transmission and drivetrain reliability
The 2009 S5 offered a 6-speed manual or a 6-speed Tiptronic automatic transmission. Some owners report issues tied to older transmissions and drivetrain hardware as miles accumulate.
Common transmission-related concerns
- Mechatronics and shifting behavior: In the automatic version, the mechatronics unit or valve body can develop wear or software-related quirks, causing harsh, delayed, or slipping shifts. Some cases benefit from software updates or component replacement.
- Clutch wear and transmission fluid: Manual transmissions may show clutch wear at higher mileages; automatics rely on regular fluid changes and proper fluid specification to maintain smooth operation.
Regular transmission service, using the manufacturer-recommended fluid, and attentive diagnosis for shifting symptoms can extend life and improve reliability.
Maintenance and inspection tips for buyers and owners
Before buying a used 2009 S5 or planning ongoing ownership, these checks help identify the most likely trouble areas and estimate future maintenance costs.
- Verify service history and look for records of timing-chain related work, oil changes with the correct synthetic oil, and cooling-system maintenance.
- Inspect for oil leaks around the engine and under the car; monitor oil consumption so you can quantify any excess usage.
- Assess the cooling system for signs of leaks or overheating history; check expansion tank and hoses, and listen for water-pump-related noises.
- Conduct a thorough inspection for carbon buildup on intake valves (especially in direct-injection engines) and plan for cleaning if necessary.
- Test the transmission’s behavior (manual or automatic) during a test drive; note any harsh shifts, slipping, or delayed engagement, and consider a software update or mechanical service if needed.
- Run a full electrical system scan to identify any persistent warning lights, battery or alternator concerns, and MMI or display faults.
With careful maintenance and timely fixes, the 2009 S5 can remain a compelling combination of performance and luxury. Prospective buyers should budget for potential major repairs tied to age and mileage, and rely on a trusted mechanic for a pre-purchase inspection.
Summary
The 2009 Audi S5’s most commonly reported problems center on engine and fuel-injection wear (oil consumption, carbon buildup), timing-chain tensioner issues, cooling-system leaks, and a range of electrical and transmission-related faults. Regular, proactive maintenance, careful inspection history, and timely addressing of warning signs can help preserve performance and reliability in this once-highly regarded luxury performance coupe.
What is the problem with the 2009 Audi S5?
Common Issues
The Audi S5 presents several areas of concern for its owners, particularly regarding reliability and maintenance costs. Many drivers report frequent mechanical issues, such as persistent oil leaks and electrical glitches, which can be both frustrating and costly to resolve.
Which year is the S5 to avoid?
After all, Audi has done a great job making sure this vehicle was incredibly durable and effective, as well as making sure it meets all performance expectations for a luxury vehicle. Rather than list all of the reliable Audi S5 models, we'll just say that you should avoid the 2013-2015 models.
Is the 2009 Audi A5 reliable?
Reliability. The 2009 Audi A5 has a 4 years / 50,000 miles basic warranty and 1 recall. RepairPal gives it a reliability rating of 4 out of 5, ranks it #6 out of 68 among Luxury Midsize Cars.
What are common problems with the Audi S5 engine?
Audi S5: Problems with carbon deposits in the 4.2 FSI engine
The engine no longer functions optimally, particularly at low engine speeds, which is noticeable in the form of stuttering and jerking. The service life of the engine is significantly impaired by these deposits if they are not treated in good time.