Ultimate family performance wagon combining practicality with supercar power. The 2.9L twin-turbo V6 is shared with Porsche, offering 450 hp and strong reliability when properly maintained. However, early production cars (2017-mid 2018) have undersized rocker arm bearings that can fail and destroy the engine - verify this has been addressed. Water pump failure can cause coolant migration into the vacuum system, risking catastrophic damage. Carbon buildup on intake valves is a long-term concern. DRC suspension needs servicing every 6 years. Requires frequent oil changes (every 10,000-12,000 km) and premium fuel. Not a casual ownership proposition, but remarkably capable when serviced religiously at specialists.
Rocker arm bearing failure (pre-06/2018)€3,500 - €17,000
Early engines have undersized needle bearings that can drop out and destroy engine · more· less
Cars built before June 8, 2018 have undersized needle bearings in the roller rockers that can drop out at high temperatures, causing catastrophic engine damage. The bearing pins can work loose due to too much play and lack of a cage. In severe cases, the loose bearings lock the outer roller race solid, scraping up and down on the cam lobe, and metal fragments can lodge in oil galleries and score main bearing journals. Audi released a revised part with needle bearings twice the original size. Replacing rocker arms preventively costs around €3,500 at specialists. If failure occurs and causes engine damage, costs can reach €17,000 or require complete engine replacement. Always verify build date and whether updated rockers have been fitted on any 2017-2018 RS4.
Water pump failure / coolant migration€3,000 - €8,900
Factory water pump leaks internally, drawing coolant into vacuum system and damaging engine · more· less
The EA839 engine has a design flaw where the water pump leaks internally when it fails. The pump uses vacuum to operate a slide valve controlling the impeller, and when it leaks, coolant is drawn into the engine's vacuum system. This can cause serious damage if sufficient coolant enters areas where it shouldn't be. Audi released TSB 2070349 in May 2023 addressing this issue. Repair costs vary from €3,000 for less severe cases to €6,700-8,900 if extensive vacuum system contamination occurs. Critical: have this checked regularly while under warranty. Affects all B9/B9.5 models with EA839 2.9T/3.0T engines from 2018-2024.
Carbon buildup on intake valves€900 - €1,800
Direct injection engines accumulate carbon deposits, restricting airflow and causing performance loss · more· less
The 2.9 TFSI uses direct injection, meaning fuel doesn't wash over intake valves like port injection. Over time, carbon deposits accumulate on valve surfaces, restricting airflow and causing rough idle, hesitation, and power loss. The "hot V" design (turbos between cylinder banks) makes walnut blasting more difficult and expensive than on conventional engines. Professional walnut blasting costs €900-1,200 at specialists, but can reach €1,800 if extensive manual cleaning is required. Labor is 10+ hours due to intake manifold removal complexity. Typically needed every 60,000-80,000 km depending on driving style. Regular spirited driving and premium fuel help delay buildup.
Rear main seal / crankshaft seal oil leak€800 - €1,500
Seal between engine and transmission known to leak on EA839 engines · more· less
The crankshaft rear main seal is a known weak point on the 2.9 TFSI EA839 engine. Multiple B9 S4/RS4 owners report oil leaks from the connection between engine and transmission. While not an immediate failure risk, it's labor-intensive to replace as the transmission must be removed. Expect 8-10 hours of labor. The seal itself costs under €50, but total repair runs €800-1,500 depending on shop rates. Some specialists recommend replacing the transmission oil pan gasket at the same time since everything is apart. Check for this while under warranty - Audi has acknowledged it as a common B9 platform issue.
Turbocharger wastegate / oil line issues€1,500 - €5,000
Wastegate fouling at high mileage, oil line leaks if service intervals stretched · more· less
Turbocharger issues are less common on the RS4 B9 than earlier generations, but failures are expensive due to twin-turbo configuration. Known problems include wastegate fouling and pressure loss at high mileage (100,000+ km), and turbocharger oil line leaks or failures if oil change intervals are stretched beyond 15,000 km. Turbo failure is typically caused by oil contamination, oil starvation, and aggressive driving without proper cool-down. Each turbo costs €1,200-1,500, plus labor. Complete twin-turbo replacement can reach €4,000-5,000. Oil changes every 10,000-12,000 km with high-quality synthetic oil (0W-40) are essential. Allow turbos to cool before shutdown after spirited driving.
DRC suspension oil leaks / system failure€2,000 - €5,500
Dynamic Ride Control dampers leak fluid after several years, recharge every 6 years · more· less
The RS4 B9 uses Audi's mechanical-hydraulic DRC system linking diagonally opposed dampers through a central valve. After several years, dampers start to leak fluid - this is a known weak point on older RS models. DRC system service (evacuate oil, renew, re-pressurize) is recommended every 6 years. Individual dampers cost €735-805 each from Audi. Most independent shops lack DRC recharging equipment. Full system replacement including all dampers and lines can cost €5,000-5,500 at dealers. Specialist refurbishment services can save 50% versus replacement. Many owners eliminate DRC entirely with conventional RS suspension, which can be more cost-effective long-term.
Brake squeal (standard steel rotors)€200 - €600
Extremely common annoyance, especially on cars without carbon ceramic brakes · more· less
Brake squeal is described by owners as "the dreaded brake squeal" that "annoys me to no end." It's particularly common on RS4s with standard steel rotors rather than optional carbon ceramics. The squealing is typically caused by brake pad vibration and can often be resolved with anti-squeal shims or different pad compounds. Audi dealers have been reluctant to fix it under warranty. Installing ceramic compound pads (not to be confused with carbon ceramic rotors) can eliminate the noise and reduce brake dust. Cost is €200-300 for aftermarket ceramic pads, or up to €600 at dealers for OEM solutions.
MMI freezes, unresponsive touchscreen, occasional software crashes · more· less
Common across the B9 platform. Symptoms include MMI freezes, unresponsive touchscreens, and occasional crashes. Most issues are resolved by software updates at dealers (free if under warranty, €100-200 otherwise). Quick fix: press and hold the volume knob for 10 seconds to reset. For persistent problems after software updates, the MMI control unit power supply may need replacement (€300-400). Note that 2017-2018 RS4 central screens are NOT touchscreen-enabled, which can be frustrating with Apple CarPlay. Always test infotainment responsiveness during pre-purchase inspection.
High-performance twin-turbo engines consume more oil, particularly as they age · more· less
Like many high-performance turbocharged engines, the 2.9 TFSI is prone to consuming more oil than average. This is considered normal by Audi for high-output engines and accelerates as the vehicle ages. Budget €100-300 per year for oil top-ups between services. Audi's specification allows up to 1 liter per 1,000 km, though most RS4s consume far less than this. Check oil level every 1,000 km and maintain proper level - low oil can cause turbocharger damage and accelerate engine wear. Use only VW 504.00/507.00 approved 0W-40 synthetic oil.
Capable but demanding - requires specialist knowledge
The RS4 B9 is significantly more reliable than previous RS4 generations when properly maintained, but it's not a casual ownership proposition. The 2.9 TFSI engine is fundamentally robust and shared with Porsche models, offering confidence in the basic design. However, early production rocker arm bearings and water pump design flaws can cause catastrophic damage if not addressed. Service history is absolutely critical - cars with full Audi dealer or specialist records and updated components (revised rocker arms, water pump monitoring) will provide years of enjoyment. Avoid heavily modified examples or those with patchy service records.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete Audi dealer or specialist service records are absolutely essential. Verify oil changes every 10,000-12,000 km maximum. Confirm coolant system maintenance and all TSB/recall work completed.
Cold start
Engine must be completely cold. Listen carefully for unusual noises, rattles, or rough idle in first 60 seconds. Any ticking or rattling can indicate rocker arm or timing chain issues.
Body condition
Check for accident damage, paint mismatch, or repair work. RS4s are often driven enthusiastically - look for curbed wheels and front end damage.
Test drive
Minimum 30 minutes including highway speeds. Test all drive modes. Listen for turbo noise, transmission smoothness, and any warning lights.
Specific for this vehicle
Verify build date and rocker arm bearing revision
Critical: If built before June 8, 2018, verify revised rocker arms have been installed. Ask for documentation. Without this, budget €3,500 for preventive replacement or risk catastrophic engine failure.
Check for coolant leaks and water pump TSB completion
Inspect for any coolant leaks around thermostat, water pump, or charge air cooler. Ask dealer to verify TSB 2070349 (water pump coolant migration) has been addressed. Check coolant level and condition.
Inspect for rear main seal oil leak
Look underneath at the connection between engine and transmission. Any oil seepage indicates rear main seal failure, requiring transmission removal (€800-1,500 repair).
Listen for turbo noises during acceleration
Accelerate hard from 2,000-6,000 RPM. Listen for unusual whistling, grinding, or hesitation. Turbos should spool smoothly with no rattles. Hesitation under boost can indicate wastegate issues.
Check DRC suspension operation
Test all suspension modes (Comfort, Auto, Dynamic, Individual). Look for oil leaks on damper bodies. Ask when DRC system was last serviced - should be every 6 years.
Verify ZF 8-speed transmission service history
Transmission fluid and filter should be changed every 60,000-80,000 km despite "lifetime fill" claims. Jerky shifting or delayed engagement indicates deferred maintenance.
Test all MMI and driver assistance functions
Test infotainment, virtual cockpit, side assist, parking sensors, and adaptive cruise. Known for software glitches - ensure all systems respond properly.
Check for carbon ceramic brakes (if equipped)
If car has optional carbon ceramics, inspect rotors for cracks or excessive wear. Replacement costs €15,000-20,000 for all four corners - this massively affects value.
Inspect exhaust system for modifications
Check if exhaust has been modified. Aftermarket exhausts can void warranty and indicate aggressive use. OEM exhaust with valve control is preferred.
Recalls and Technical Service Bulletins
Water pump coolant migration (TSB 2070349, May 2023)Verify addressed
Rocker arm bearing revision (pre-06/2018 production)Verify completed
Charge air cooler internal leaking (Audi bulletin)Check for fractures
MMI software updates (various)Ensure latest version
Contact Audi dealer with VIN to verify all recalls and TSBs have been completed. The rocker arm bearing and water pump issues are particularly critical and can cause catastrophic engine damage if not addressed.
Warranty Status
Factory warranty (2 years unlimited km)Expired on all 2017-2022 models
Extended warranty available€2,000-3,500/year
Drivetrain warranty (3 years/100,000 km)Check if still active
All RS4 B9s from 2017-2022 are outside their original factory warranty. Extended warranty through Audi dealers is available but expensive (€2,000-3,500 annually). Read exclusions carefully - some critical items like DRC suspension oil leaks and certain electronic failures may not be covered. Independent specialists often provide better value for high-mileage maintenance than trying to maintain warranty coverage.
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.