Audi RS4/RS5 B8 Buying Guide

The Audi RS4 and RS5 B8 are iconic models within Audi’s high-performance RS line. With their 4.2-litre V8 engines, they offer impressive power, sharp handling, and everyday usability. However, before considering a purchase, it’s important to understand the common issues these vehicles face and what to look for when buying a used RS4 or RS5.

Here’s a comprehensive guide to help potential buyers make an informed decision.

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Engine and Performance

The RS4 and RS5 B8 are both powered by Audi’s 4.2-litre naturally aspirated V8. This engine offers 420 horsepower in the RS4 and 450 horsepower in the RS5. While these are robust engines, some key areas require attention:

• Timing Chain and Tensioners: The V8 engines in these models are chain-driven, but over time, the timing chain and tensioners can wear out. A rattling sound from the front of the engine could indicate a failing timing chain or tensioner, and replacing these components can be expensive. Be sure to listen for any unusual noises during a test drive.
• Carbon Build-up: Like many direct-injection engines, the 4.2 V8 is susceptible to carbon build-up on the intake valves. This can cause rough idling, misfires, or a loss of power. Regular carbon cleaning is required to keep the engine running smoothly, but make sure the vehicle has had this service performed or factor it into your maintenance costs.
• Oil Consumption: The V8 engine may consume oil, especially as it ages. Check the oil level frequently and ensure there are no signs of oil leaks around the engine bay. Low oil levels can cause significant engine damage if left unchecked.

Transmission and Drivetrain

Both the RS4 and RS5 B8 come with Audi’s S-tronic dual-clutch gearbox. These transmissions are generally reliable but can show signs of wear:

• Clutch Wear: If the car has been driven aggressively, the clutch can wear prematurely. Be aware of any signs of slipping or jerky gear changes, especially in low-speed driving conditions. A full replacement of the clutch and flywheel can be costly.
• Transmission Issues: While the S-tronic is a high-performance gearbox, it can occasionally experience issues with the mechatronic unit. Symptoms may include delayed shifting or a failure to engage gears. It's a good idea to check the gearbox for smooth operation and test the car in various driving conditions.
• Quattro System: Audi’s Quattro all-wheel-drive system is a key selling point of these models, providing superb handling and stability. However, be sure to inspect the condition of the driveshafts, differential, and related components for any signs of excessive wear or damage.

Suspension and Handling

The RS4 and RS5 B8 come with a sportier suspension setup than their standard A4 or A5 counterparts, and both feature dynamic ride control. However, these components are subject to wear and tear, particularly with higher mileage:

• Suspension Components: The suspension bushings, ball joints, and dampers can wear over time, leading to a decrease in handling performance and comfort. Listen for any knocking noises when driving over bumps, as this could indicate worn suspension components.
• Magnetic Ride Control: If the car is equipped with Audi’s magnetic ride suspension, it’s crucial to ensure that the system is working correctly. A malfunctioning magnetic ride system can lead to a compromised ride quality and expensive repairs.

Brakes

The RS4 and RS5 B8 are equipped with large, high-performance brakes that provide excellent stopping power. However, due to their size and performance capabilities, they can experience wear:

• Brake Discs and Pads: These models have high-performance brake discs that can wear down faster than standard brakes. Make sure to inspect the condition of the brake discs and pads, particularly on cars that have seen track use or aggressive driving.
• Brake Fluid and Lines: The brake fluid should be changed regularly to maintain optimal braking performance. Make sure to check for any leaks or signs of wear in the brake lines, especially in older vehicles.

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Interior and Electronics

While the Audi RS4/RS5 B8 is built with quality materials, electrical issues can crop up over time:

• Infotainment System: Audi’s MMI system can occasionally have issues with responsiveness or display failures. Test the MMI system thoroughly to ensure it is working correctly. If the system is unresponsive or slow, it might require software updates or repairs.
• Seats and Upholstery: The RS models come with sportier, more supportive seats, which can show wear, especially on high-mileage examples. Check for any rips, stains, or excessive bolster wear. Additionally, the electric seat functions should be tested to ensure they operate smoothly.

General Maintenance and Service History

As with any performance car, proper maintenance is crucial to the longevity and reliability of the RS4/RS5 B8. Ensure the car you’re considering has a full service history, ideally with records from an Audi dealership or reputable specialist. Pay particular attention to:

• Regular Oil Changes: Audi recommends frequent oil changes, particularly with these high-performance engines. Ensure that the car has had regular oil changes at the correct intervals.
• Cam Belt and Water Pump: If the car has reached the recommended mileage for a timing belt replacement, make sure the previous owner has had this done. Replacing the cam belt and water pump can be expensive but is necessary to avoid significant engine damage.
• Upgrades and Modifications: Many owners of the RS4/RS5 B8 opt for performance upgrades, such as aftermarket exhaust systems or tuning chips. While these modifications can enhance the car’s performance, they can also lead to potential reliability issues. If the car has been modified, ask for details on the modifications and whether any additional maintenance has been carried out to support them.

Common Faults

Some common issues owners of the RS4/RS5 B8 have reported include:

• Battery Drain: Older models may experience battery drain due to faulty electronic modules or alternators. Make sure to check the condition of the battery and charging system.
• Coolant Leaks: Some owners have reported coolant leaks around the radiator or hoses. Inspect the radiator for any signs of damage or leaks, particularly if the car has been parked outside for long periods.

Conclusion

The Audi RS4 and RS5 B8 are exceptional cars, offering a thrilling driving experience and a mix of performance and luxury. However, like any performance car, they come with their own set of potential issues that should be carefully considered before purchase. By paying attention to the engine, transmission, suspension, and general maintenance history, you can ensure that you’re investing in a well-maintained example that will provide years of driving pleasure.

Always have a pre-purchase inspection performed by a specialist before finalising the deal, as this can save you from costly repairs down the line.