The 2019 S4 with the EA839 3.0T V6 is generally solid, but the dual-clutch transmission (DQ500 7-speed S tronic) has cooling issues, and earlier B9 platform cars suffered catastrophic engine failures due to defective piston rings—though 2019 models are mostly outside the danger zone.
Transmission Oil Cooler Failure (DQ500 DSG)
Common · high severityTypical onset: 40,000-80,000 mi
Symptoms: Check engine light with transmission temp codes (P17BF, P17F8), Delayed shifts or rough engagement when hot, Transmission goes into limp mode during spirited driving or hot weather, Coolant mixing with ATF (less common but catastrophic)
Fix: Replace transmission oil cooler and flush both transmission fluid and coolant system. Requires dropping undertray and partial front bumper removal. 4-6 hours labor depending on shop familiarity. Many owners also replace the thermostat and upgrade to larger aftermarket coolers to prevent recurrence.
Estimated cost: $1,200-2,500
Transmission Mount Failure
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Clunking when shifting from Park to Drive or Reverse, Excessive driveline movement during hard acceleration, Vibration at idle that changes with load, Visible tearing or oil saturation in the rubber mount
Fix: Replace transmission mount (often the lower/rear mount). On a lift this is a 2-3 hour job—support transmission, unbolt mount, swap, reinstall. The OEM part is hydraulic-filled and prone to rupture from launch control abuse or spirited driving. Upgraded polyurethane mounts available but increase NVH.
Estimated cost: $400-800
Fuel Filter Clogging (High-Pressure In-Tank)
Occasional · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Rough idle or misfires under boost, Loss of power above 4,000 RPM, Fuel pressure faults (P0087, P0088), Long crank time or hard starts when hot
Fix: Replace in-tank high-pressure fuel filter assembly. Requires dropping the fuel tank, disconnecting lines, and replacing the entire filter unit. 3-4 hours labor. Audi doesn't list this as a service item, but direct-injection systems are sensitive to contamination. Use Top Tier fuel to extend life.
Estimated cost: $600-1,200
Timing Chain Tensioner and Guide Wear (Late Production)
Rare · high severityTypical onset: 80,000-120,000 mi
Symptoms: Cold-start rattle for 2-3 seconds (sounds like diesel), Check engine light with cam correlation codes (P000A, P000B), Metallic chain noise at idle, Loss of power and misfires if chain skips
Fix: Replace timing chain, tensioners, and guides on both banks. Requires removing front of engine, possibly turbos depending on access. 12-16 hours labor. The EA839 is mostly reliable here, but some 2018-2019 cars show premature wear, likely from extended oil change intervals or low-quality oil. Catastrophic if ignored.
Estimated cost: $4,000-7,000
PCV Valve and Carbon Buildup (Direct Injection)
Occasional · low severityTypical onset: 60,000-90,000 mi
Symptoms: Rough idle and stumble on cold start, Oil consumption increase (1 qt per 2,000 mi or more), Check engine light for lean/rich bank codes, Whistling or hissing from intake side
Fix: Replace PCV valve and diaphragm assembly, and walnut-blast intake valves. PCV is 2 hours, carbon cleaning adds 4-6 hours (intake manifold off). Direct-injection cars need valve cleaning every 40,000-60,000 miles. The EA839 has improved catch-can provision from factory, but it's not a cure. Add an aftermarket catch can if keeping long-term.
Estimated cost: $800-1,800
Buy a 2019 S4 if you want a Q-car daily with real performance, but set aside $2,000/year for transmission and drivetrain maintenance—these aren't Toyota-cheap to own long-term.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.