The B9 S5 replaced the previous supercharged 3.0 TFSI with a new turbocharged V6 (EA839), co-developed with Porsche and paired with the proven ZF 8-speed automatic. Available as Coupe, Sportback, and Cabriolet, it offers 354 hp through a permanent quattro system. Availability differs by body style: Audi published German technical data for the 260 kW Coupe in May 2016, the Coupe and Sportback moved to a 3.0 TDI at the B9.5 facelift, and the facelifted Cabriolet kept the 3.0 TFSI through 2024. The EA839 engine is capable but has several known weak points that require informed ownership.· more· less
Strong turbocharged V6, refined chassisZF 8-speed gearbox is proven reliable
Water pump design flaw on EA839Rocker arm risk on pre-mid-2018 cars
Buy if: You want a refined performance coupe or sportback with quattro AWD and can verify the water pump has been updated and rocker arms are revised on early cars.
Avoid if: You cannot budget for potentially expensive cooling system or engine repairs, or are considering a pre-2018 car with unconfirmed component revisions.
Internal pump seal fails, drawing coolant into the engine vacuum system and potentially causing serious damage · more· less
The EA839 water pump uses vacuum actuation to control a slide valve inside the pump housing. When the internal seal degrades, coolant leaks into the vacuum system rather than externally, making the failure difficult to detect visually. The coolant can migrate to turbo wastegate actuators, brake booster lines, and the vacuum reservoir. Audi acknowledged this with TSB 2058890. Specialist shops report this regularly on cars from around 60,000-100,000 km. If caught early (unexplained coolant loss, P0299 underboost code), replacing the pump alone costs approximately 1,500-2,000 euros. If the vacuum system is contaminated, the repair escalates to 3,000-4,500 euros as multiple solenoid valves, lines, and the vacuum reservoir need replacement. The revised pump uses a 6-bolt pulley instead of the original 4-bolt design, making it easy to check visually. The piston skirt warranty extension that is often cited alongside this repair is an Audi of America and Canada programme and does not cover the water pump in any case.
Rocker arm needle bearing failure (pre-mid-2018)
up to €8,0002 of 7
Undersized needle bearings in rocker arms can collapse under sustained high-RPM use, causing valve train damage · more· less
Early EA839 engines (produced before approximately August 2018) used rocker arms with small needle roller bearings that were undersized for the loads involved. Under sustained high RPM or high temperature conditions, the needle bearings can disintegrate and fall into the valve train, potentially damaging camshafts, cam position sensors, and cylinder head surfaces. The failure typically presents as a loud ticking noise, much louder than the normal injector/HPFP tick. Audi revised the rocker arm design with significantly larger bearings in mid-2018. Specialist repair at an independent shop runs approximately 3,000-5,000 euros depending on the extent of the damage. If Audi diagnoses severe damage, they may quote a full engine replacement at 15,000-25,000 euros, though specialists can usually repair the affected components for far less. This primarily affects 2017 and early 2018 production cars.
PCV hose check valve failure
up to €1,2003 of 7
Internal membrane in the PCV hose fails, causing excessive crankcase pressure and oil leaks around the oil filler cap · more· less
The Positive Crankcase Ventilation system uses a check valve integrated into the breather hose. When the internal membrane tears, crankcase pressure rises, which can blow the oil filler cap loose and spray oil over the engine bay. In severe cases this has led to small engine fires. Symptoms include a wandering idle between 1,000 and 2,500 RPM, a whistling noise from under the bonnet, and unusually strong suction when trying to remove the oil cap with the engine running. Audi issued a TSB with improved components for 2017-2019 models. The PCV solenoid valve part itself costs approximately 40-60 euros, but accessing the PCV system on the EA839 requires removing the intake manifold, bringing total repair costs to 400-800 euros at a specialist. If the turbocharger area also needs cleaning or attention due to oil contamination, costs can reach 1,200 euros.
Valve sticks or cracks, causing intermittent overheating warnings or coolant leaks · more· less
The thermal management valve regulates coolant flow through various engine circuits for optimized warm-up and operating temperature. The internal diaphragm is prone to cracking, causing the valve to stick open or leak externally. This can also be triggered as secondary damage from a failed water pump pushing coolant into the vacuum system. Symptoms include intermittent overheating warnings, visible coolant drips near the valve, and fault codes P0597 or P2681. The valve itself costs approximately 80-120 euros, with labor adding 200-400 euros. Many owners do not notice the leak until it worsens, as initial leakage is often minimal. This failure is common enough that replacing it preventively during a water pump service is often recommended.
Oil filter housing gasket leak
up to €1,5005 of 7
Plastic oil filter housing develops cracks or gasket deteriorates, causing external oil seepage near the turbocharger · more· less
The plastic oil filter housing is positioned near the turbocharger wastegate actuator and is prone to developing leaks at the gasket surface. The leak can be mistaken for an oil pan leak due to oil running down the engine. On the EA839, accessing the housing requires partial removal of surrounding components, making this a labor-intensive repair. Parts cost approximately 100-200 euros, but labor runs 3-6 hours at a specialist. At an Audi dealer, total cost can reach 1,200-1,500 euros. Many independent specialists can complete the job for 500-800 euros. This issue typically appears from around 80,000 km onward.
Hydraulic engine mount deterioration
up to €9006 of 7
Fluid-filled mounts leak hydraulic fluid, causing vibrations at idle and clunking when shifting into gear · more· less
The B9 S5 uses electronically controlled hydraulic engine mounts designed to balance engine support with cabin refinement. These mounts are filled with hydraulic fluid that can leak as the rubber seals age. Failed mounts produce noticeable vibrations at idle (particularly in Drive at a standstill), clunking when engaging Drive or Reverse, and increased NVH at low speeds. Mounts typically last 80,000-120,000 km depending on driving style. Replacement costs approximately 200-250 euros per mount for OEM parts, with labor at 2-3 hours per side. Total cost for a pair is approximately 600-900 euros at a specialist, somewhat less if only one mount has failed.
Piston skirt wear (EA839 design concern)
up to €15,0007 of 7
Piston design allows excessive rocking which can cause skirt wear, scoring, and in rare cases engine failure · more· less
A documented design limitation in the EA839 engine involves piston instability (rocking) within the cylinder bore. Machined oil drain holes act as stress risers, and over time, cyclic loading can cause cracks in the ringland area. This leads to combustion gas leakage and piston damage. While dramatic, the observed failure rate is well below 5% and Audi has released three piston revisions, indicating they acknowledge the issue. One dealership reported 14 cases in a 6-week period, but across the entire EA839 production this remains rare. The warranty extension usually quoted for this defect is Audi of America and Canada action U82/53ZC, which runs to 8 years or 80,000 miles (129,000 km) and applies only to vehicles that meet its eligibility criteria. There is no evidence of an equivalent blanket European programme covering all EA839 models, so ask Audi to confirm what applies to the specific VIN in your market. Signs include unusual oil consumption (more than 1L per 5,000 km), blue exhaust smoke, and misfires. If the failure occurs outside warranty, repair typically requires a partial or full engine rebuild costing 5,000-15,000 euros depending on the extent of damage.
Known cooling system and early-production issues require careful buying
The EA839 turbocharged V6 is fundamentally capable and many examples exceed 150,000 km without major powertrain problems. However, the water pump design flaw is a genuine concern on all B9 S5s and should be the primary focus of any pre-purchase inspection. Early production cars (2017 to mid-2018) additionally carry rocker arm risk. Post-mid-2018 cars with the revised water pump and rocker arms are notably lower risk. The ZF 8-speed gearbox is one of the most reliable automatics available and is rarely a source of problems.
Service history
Complete Audi dealer or specialist records essential. Verify oil changes every 15,000 km or annually.
Tires
Check tread depth, age (date codes), and uneven wear. Rear tires wear faster on quattro S models.
Cold start
Start engine completely cold. Listen for unusual ticking or rattling in the first 30 seconds.
Test drive
Minimum 30 minutes including highway driving to bring engine and transmission up to full operating temperature.
Specific for this vehicle
Check water pump pulley bolt count
A 6-bolt pulley indicates the revised pump. A 4-bolt pulley means the original design is still fitted. Budget for replacement if original.
Check coolant level and look for unexplained loss
The EA839 water pump leaks internally, not externally. Declining coolant level with no visible leak is a key warning sign.
Listen for loud ticking at idle (rocker arms)
A ticking noise louder than normal injector/fuel pump sound, especially on pre-mid-2018 cars, may indicate rocker arm bearing failure.
+ 4 more checksShow less
Check oil filler cap for oil residue
Oil spray around the cap or in the engine bay indicates PCV valve failure. Try removing the cap with the engine running: excessive suction or pressure is abnormal.
Inspect engine mounts for fluid leaks
Look underneath the hydraulic mounts for any oil seepage. Test by engaging Drive at a standstill with the brake held: excessive vibration suggests worn mounts.
Check production date for component revisions
Cars produced after approximately August 2018 have revised rocker arms. Verify with the VIN or build sticker whether the car falls before or after this date.
Monitor oil consumption during test drive
Check oil level before and after an extended test drive. Excessive oil consumption (more than 1L per 5,000 km) may indicate piston skirt wear.
Recalls and Technical Service Bulletins
Affected factory-fitted 265/30 ZR20 Dunlop tyres — German campaign 44O6, KBA 8372, certain 2017-2018 A5 and S5 vehicles with that equipmentVerify with VIN
Contact Audi with the VIN to verify whether German tyre campaign 44O6 applies and has been completed; applicability depends on the factory-fitted wheel and tyre combination.
Warranty Status
Factory warranty (2 years)Expired on all used B9 S5 TFSI models
Piston skirt warranty extensionDocumented for the US and Canada; ask Audi what applies in your market
Rust perforation warranty (12 years)May still be active on 2017-2019 cars
All B9 S5 3.0 TFSI models are outside their original 2-year factory warranty. The piston skirt warranty extension that is widely quoted for this engine is Audi of America and Canada action U82/53ZC, running to 8 years or 80,000 miles (129,000 km) with vehicle-specific eligibility. Do not assume the same cover exists in Europe: ask Audi to confirm against the VIN what programme, if any, applies in the car's market.
Sources: Research draws on model-specific owner forums and owner communities, recall information from official authorities, German automotive press, and multiple workshop cost references cross-checked against each other.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.
