The Audi A5 F5 S5, introduced in 2017, is a high-performance luxury coupe, convertible, and Sportback variant of the Audi A5 lineup. Powered by a turbocharged 3.0-litre V6 engine, the F5 S5 combines Audi's iconic Quattro all-wheel-drive system with refined handling, cutting-edge technology, and a dynamic driving experience. As one of the standout models in the Audi range, the S5 is known for its power, precision, and luxury mix. However, despite its high engineering and performance standards, the Audi A5 F5 S5 is not immune to mechanical and electrical problems. Over time, various issues can arise, particularly in older models or vehicles that must be adequately maintained.
This comprehensive guide explores the common issues associated with the Audi A5 F5 S5, discussing symptoms, causes, and solutions to help owners maintain their vehicles in top condition.
Audi A5 F5 S5 Turbocharger Issues
The Audi A5 F5 S5 is powered by a 3.0-litre turbocharged V6 engine that delivers impressive performance. While the turbocharger significantly enhances power output, it is also a complex and high-stress component that can experience wear and failure over time, especially in vehicles with high mileage or those subjected to aggressive driving.
Symptoms of Turbocharger Failure
Loss of power: One of the most noticeable symptoms of turbocharger failure is a significant reduction in engine power, particularly during acceleration. The engine may feel sluggish, and the car may struggle to reach high speeds.
Whistling or whining noise: A high-pitched whistling or whining noise, especially under load, is often a sign that the turbocharger's internal components, such as the bearings or turbine, are worn or damaged.
Increased fuel consumption: As the turbocharger becomes less efficient, the engine may burn more fuel to compensate for the loss of boost pressure, reducing fuel economy.
Excessive exhaust smoke: Blue or black smoke from the exhaust may indicate that oil leaks into the turbocharger and is burned during combustion.
Check engine light: Turbocharger issues can trigger the check engine light due to problems with boost pressure or air intake.
Causes and Diagnosis
Turbocharger failure is commonly caused by oil contamination, starvation, or general wear and tear on internal components. Infrequent oil changes, low-quality oil, or leaks can accelerate wear on the turbocharger's bearings and turbine. Aggressive driving without allowing the turbocharger to cool down can lead to overheating, which damages the internal components.
A mechanic can diagnose turbocharger problems by inspecting for oil leaks, listening for unusual noises during acceleration, and using diagnostic tools to check for fault codes related to boost pressure or air intake.
Repair and Maintenance Solutions
Replacing the entire unit is typically the best solution if the turbocharger fails. While rebuilding the turbocharger is an option, it may not be as reliable as a total replacement. In cases where the turbocharger failure is caused by oil contamination, it is essential to inspect and replace the oil feed and return lines to ensure proper lubrication for the new turbo.
To prevent turbocharger issues, regular oil changes with high-quality synthetic oil are essential to maintain proper lubrication and prevent premature wear. Additionally, allowing the turbocharger to cool down after spirited driving can help prevent overheating and extend its lifespan.
Audi A5 F5 S5 Timing Chain Tensioner Problems
The Audi A5 F5 S5 uses a timing chain rather than a timing belt. While timing chains are generally considered more durable, they are not immune to problems, particularly with the timing chain tensioner. A faulty tensioner can cause the timing chain to become loose or stretched, leading to engine misfires, rough idling, and even catastrophic engine failure if the chain jumps teeth.
Symptoms of Timing Chain Tensioner Failure
Rattling noise at startup: A common sign of timing chain tensioner failure is a rattling noise during cold starts. This occurs because the tensioner relies on oil pressure to maintain proper tension on the chain, and when oil pressure is low, the chain may become loose.
Check engine light: Timing chain issues can trigger the check engine light, often with fault codes related to the camshaft or crankshaft position errors or timing misalignment.
Engine misfires: A loose or stretched timing chain can throw off the engine's timing, resulting in misfires, rough idling, and reduced performance.
Loss of power: If the timing chain has stretched or jumped teeth, the engine may lose power due to improper valve timing.
Difficulty starting the engine: In severe cases, a loose or stretched timing chain can cause the engine to have trouble starting, especially after the car has been sitting for an extended period.
Causes and Diagnosis
Timing chain tensioner problems are typically caused by wear and tear over time. The tensioner relies on oil pressure to maintain proper tension on the chain, and inadequate lubrication due to infrequent oil changes or low-quality oil can accelerate wear on the tensioner and the chain components. Early Audi A5 F5 S5 models were known to have weaker tensioners that could fail prematurely.
A mechanic can diagnose timing chain tensioner problems by listening for unusual noises during startup and inspecting the timing chain for slack or signs of stretching. Diagnostic tools can also be used to check for timing-related fault codes.
Repair and Maintenance Solutions
If the timing chain tensioner has failed, replacing the tensioner and the timing chain is usually necessary. Due to the timing chain's location deep within the engine, this is a labor-intensive and expensive repair. In some cases, the chain guides may also need to be replaced if they have been damaged by a loose chain.
Regular oil changes with high-quality synthetic oil are crucial to prevent timing chain issues and ensure proper lubrication of the timing components. If you hear unusual noises during startup or experience rough idling, it is essential to have the timing chain system inspected immediately to avoid further damage.
Audi A5 F5 S5 Carbon Buildup on Intake Valves
The Audi A5 F5 S5 uses direct fuel injection, which improves fuel efficiency and performance by injecting fuel directly into the combustion chamber. However, this design can also lead to carbon buildup on the intake valves, as fuel does not pass over them to clean them. Over time, carbon deposits can accumulate, restricting airflow and causing performance issues.
Symptoms of Carbon Buildup
Rough idling: Carbon buildup on the intake valves can cause the engine to idle roughly or inconsistently, especially when cold. This is often one of the first signs of carbon buildup.
Poor throttle response: The engine may feel sluggish or unresponsive during acceleration due to restricted airflow caused by carbon deposits.
Reduced power: Carbon buildup can result in a noticeable decrease in power, particularly at higher RPMs, where airflow restrictions are more pronounced.
Decreased fuel efficiency: The engine may use more fuel as it compensates for restricted airflow, reducing fuel efficiency.
Engine misfires: In severe cases, carbon buildup can cause the engine to misfire, especially during cold starts or under heavy load.
Causes and Diagnosis
Carbon buildup occurs when oil vapours and combustion byproducts accumulate on the intake valves. Since the fuel does not pass over the intake valves in direct injection engines, these deposits are not burned off during combustion. This issue is more common in vehicles frequently driven in stop-and-go traffic or for short distances, as the engine may need to reach the high temperatures required to burn off carbon deposits.
A mechanic can diagnose carbon buildup by inspecting the intake valves with a borescope for deposits. If significant carbon buildup is found, cleaning the intake valves will be necessary to restore engine performance.
Repair and Maintenance Solutions
The most effective method for removing carbon buildup is walnut blasting, in which crushed walnut shells are blasted at high pressure to clean the intake valves without damaging them. Chemical cleaners are also available but are generally less effective for severe carbon buildup.
Regular maintenance is essential to prevent carbon buildup. Using high-quality fuel and oil, installing an oil catch can reduce oil vapour entering the intake system, and periodically driving the vehicle at higher speeds can help minimize carbon buildup.
Oil Consumption Issues
The Audi A5 F5 S5 is known to have issues with excessive oil consumption, particularly in earlier models. While some oil consumption is average for a turbocharged engine, many S5 owners report that their vehicles consume more oil than expected. Excessive oil consumption can lead to more frequent oil top-ups and, if left unchecked, can result in engine damage due to low oil levels.
Symptoms of Excessive Oil Consumption
Frequent need to top up oil: Adding oil between service intervals more frequently than expected could be a sign of excessive oil consumption.
Blue smoke from the exhaust: Blue smoke, especially during acceleration or after idling, indicates oil is burned in the combustion chamber.
Burning oil smell: A strong smell of burning oil, particularly after driving, may indicate oil leaking into the combustion chamber.
Check oil level warning light: If the oil level drops too low, the vehicle's ECU will trigger a warning light on the dashboard, alerting you to check the oil level.
Decreased performance: Running the engine with low oil levels can lead to reduced performance and increased engine wear.
Causes and Diagnosis
Excessive oil consumption in the Audi A5 F5 S5 is often caused by worn piston rings or valve seals, which allow oil to seep into the combustion chamber, where it is burned off. Another common culprit is a malfunctioning Positive Crankcase Ventilation (PCV) system, which can cause excess oil vapour to enter the intake manifold and be burned during combustion.
A mechanic can diagnose excessive oil consumption by performing a compression or leak-down test to assess the condition of the piston rings and valve seals. The PCV system must also be inspected for any blockages or malfunctions contributing to the issue.
Repair and Maintenance Solutions
Excessive oil consumption may require replacing worn piston rings or valve seals, which can be labour-intensive and expensive. If significant damage has occurred, the engine may need to be rebuilt.
If the PCV system is found to be the cause of the oil consumption, cleaning or replacing the PCV valve may resolve the issue. Regular oil changes with high-quality synthetic oil can also help reduce oil consumption by keeping the engine's internal components adequately lubricated.
It is essential to monitor and top up oil levels regularly to avoid running the engine with low oil, which can lead to more severe damage and costly repairs.
Water Pump and Thermostat Failure
Cooling system issues, particularly with the water pump and thermostat, are common in the Audi A5 F5 S5. The water pump circulates coolant through the engine to regulate its temperature, while the thermostat controls the flow of coolant to ensure the engine operates within its optimal temperature range. Over time, these components can wear out, leading to cooling system problems and potential engine overheating.
Symptoms of Water Pump or Thermostat Failure
Fluctuating engine temperatures: If the thermostat is stuck open or closed or the water pump fails, the engine's temperature may fluctuate or rise to dangerous levels.
Coolant leaks: A failing water pump can cause coolant leaks, which may result in visible puddles of coolant under the vehicle after it has been parked.
Poor heater performance: If the water pump or thermostat malfunctions, the vehicle's heater may blow cold air even when the engine is warm.
Engine overheating: If the water pump or thermostat fails completely, the engine may overheat, leading to significant damage, such as a warped cylinder head or blown head gasket.
Coolant warning light: The vehicle's dashboard may display a coolant warning light if the engine is overheating or the coolant level is too low.
Causes and Diagnosis
Water pump and thermostat failures are often caused by wear and tear over time. The water pump's seals and bearings can wear out, leading to coolant leaks and reduced cooling capacity. The thermostat can become stuck in the open or closed position, preventing the engine from maintaining the correct temperature. Coolant leaks can also occur due to cracked hoses, loose clamps, or a faulty radiator.
A mechanic can diagnose cooling system issues by inspecting the water pump and thermostat for signs of wear or failure. A pressure test can also be performed to check for coolant leaks.
Repair and Maintenance Solutions
Repairing cooling system issues typically involves replacing the faulty water pump, thermostat, or any damaged hoses or components. Sometimes, the entire cooling system may need to be flushed and refilled with fresh coolant.
Preventing water pump and thermostat issues involves regular coolant flushes and inspections of the water pump, thermostat, and hoses to ensure they function correctly. Monitoring the engine's temperature gauge and promptly addressing warning lights or leaks can help avoid severe engine damage.
Brake Wear and Rotor Warping
The Audi A5 F5 S5 is equipped with high-performance brakes designed to handle spirited driving demands. However, brake wear and rotor warping are common issues, particularly in vehicles driven aggressively or used for track days. Worn brake pads and warped rotors can affect braking performance, increasing stopping distances and reducing safety.
Symptoms of Brake Wear and Rotor Warping
Squealing or grinding noises: Worn brake pads can produce squealing or grinding noises, especially when applying the brakes.
Brake pedal vibration: Warped rotors can cause the brake pedal to vibrate or pulsate during braking.
Reduced braking performance: Worn brake pads or warped rotors can lead to increased stopping distances and reduced braking effectiveness.
Uneven brake wear: Inconsistent brake pad wear or rotor warping can cause uneven braking performance, with the car pulling to one side when braking.
Brake warning light: The brake warning light may illuminate if the brake pads are excessively worn or if there is an issue with the braking system.
Causes and Diagnosis
Brake wear is a natural result of regular use, especially in high-performance vehicles like the S5 that are frequently driven aggressively. Warped rotors are often caused by excessive heat buildup during hard braking, which can cause the rotors to become uneven. This issue is more common in vehicles on the track or for frequent high-speed driving.
A mechanic can diagnose brake wear and rotor warping by inspecting the brake pads and rotors for signs of wear or damage. They may also measure the thickness of the brake pads and rotors to determine if replacement is necessary.
Repair and Maintenance Solutions
Repairing brake wear typically involves replacing the brake pads and, in some cases, the rotors. Depending on the severity of the warping, warped rotors may need to be resurfaced or replaced. To ensure optimal braking performance in the S5, it is essential to use high-quality performance brake pads and rotors.
Avoid hard braking, especially during high-speed driving, to prevent brake wear and rotor warping. Regularly inspecting the brake system and replacing brake pads before they become too worn can also help prevent damage to the rotors.
Fuel Injector Problems
The fuel injectors in the Audi A5 F5 S5 deliver precise amounts of fuel to the combustion chambers. Over time, injectors can become clogged or fail, leading to poor engine performance and increased fuel consumption. This issue is more common in high-mileage vehicles or those that need to be properly maintained.
Symptoms of Fuel Injector Failure
Rough idling: A clogged or faulty fuel injector can cause the engine to idle roughly or inconsistently.
Engine misfires: Poor fuel delivery can result in engine misfires, particularly under load or during acceleration.
Increased fuel consumption: A malfunctioning fuel injector can cause the engine to burn more fuel than necessary, reducing fuel efficiency.
Excessive exhaust smoke: If a fuel injector leaks or clogs, it can cause incomplete combustion, resulting in black smoke from the exhaust.
Check engine light: Injector issues often trigger the check engine light, with fault codes related to fuel delivery or injector performance.
Causes and Diagnosis
Fuel injector problems are typically caused by wear and tear, contamination from low-quality fuel, or carbon buildup. Over time, deposits can clog the injectors, reducing their effectiveness. Poor fuel system maintenance, such as infrequent fuel filter replacements, can exacerbate these issues.
A mechanic can diagnose fuel injector problems by inspecting the injectors for visible signs of clogging or using diagnostic tools to check for fault codes related to fuel delivery.
Repair and Maintenance Solutions
Repairing fuel injector problems usually involves cleaning or replacing the faulty injectors. In some cases, fuel system cleaners can remove carbon deposits and restore injector performance. However, if the injectors are severely worn or damaged, they may need to be replaced.
To prevent fuel injector issues, it is essential to use high-quality fuel and replace the fuel filter at recommended intervals. Periodically using a fuel system cleaner can also help keep the injectors clean and reduce the likelihood of clogging.
Electrical and Sensor Failures
The Audi A5 F5 S5 has a wide range of advanced electronic systems and sensors that control everything from engine performance to driver assistance features. Electrical issues and sensor failures are relatively common in modern vehicles, particularly as they age, and can affect various systems within the car.
Symptoms of Electrical and Sensor Problems
Dashboard warning lights: Faulty sensors or electrical connections can trigger warning lights, such as the check engine or ABS light.
Erratic behaviour of electronic systems: Electrical issues can cause malfunctions in systems like the power windows, climate control, or infotainment system.
Poor engine performance: Sensor failures, particularly in components like the Mass Air Flow (MAF) sensor or oxygen sensors, can lead to poor engine performance and reduced fuel efficiency.
Inaccurate gauge readings: Faulty sensors can cause the vehicle's gauges to display incorrect information, such as engine temperature or fuel level.
Causes of Electrical and Sensor Failures
Electrical issues are often caused by aging wiring, corroded connectors, or failing relays. Sensors can fail due to exposure to heat, oil contamination, or general wear and tear over time. Poor maintenance of electrical components can exacerbate these issues, leading to more frequent malfunctions.
A mechanic can diagnose electrical and sensor problems using diagnostic tools to check for fault codes and inspect the vehicle's wiring and electrical components for signs of wear or damage.
Repair and Maintenance Solutions
Repairing electrical and sensor issues typically involves replacing faulty sensors, cleaning corroded connectors, or repairing damaged wiring. Sometimes, a software update may be necessary to resolve the electronic problems.
Regular maintenance of the vehicle's electrical system, including checking for loose or corroded connections and replacing sensors at recommended intervals, can help prevent common electrical problems.
Conclusion
The Audi A5 F5 S5 is a luxurious and powerful sports coupe that offers exhilarating performance, advanced technology, and refined driving dynamics. However, like any high-performance vehicle, it is prone to specific mechanical and electrical issues as it ages. From turbocharger problems and timing chain tensioner failures to excessive oil consumption and brake wear, understanding these challenges and addressing them proactively is essential to maintaining the vehicle's performance and longevity.
Regular maintenance, timely repairs, and a proactive approach to troubleshooting are vital to keeping the Audi A5 F5 S5 running smoothly. If you experience these common issues, professional assistance is often required to ensure proper diagnosis and repair. At European Auto Pro, our experienced technicians specialize in Audi repairs, offering expert solutions tailored to your vehicle's needs. Visit us at 253 Goodwood Road, Kings Park, 5034 South Australia, for comprehensive service and reliable repairs to keep your Audi performing at its best.