Used Audi S5 B9 (2018-2024): Buyer's Guide

The B9 Audi S5 is the rare performance car that can be a coupe, a convertible, or a genuinely useful hatchback without changing its mechanical character. Every US-market example uses a turbocharged 3.0-liter V6, an eight-speed automatic, and quattro all-wheel drive. A 2018 Car and Driver test put the Sportback at 60 mph in 4.3 seconds, yet the same car returned 33 mpg in that publication's highway test and swallowed 22 cubic feet of luggage behind its rear seats.

That breadth makes the S5 easy to recommend and dangerously easy to buy on appearance alone. Early engines can carry the old rocker-arm design associated with costly valvetrain damage. Across the generation, the water pump can leak coolant into vacuum-system components, active engine mounts can fail, and front control-arm bushings wear. Owners also report five-figure worst cases when a small warning was allowed to become internal engine damage.

The good news is that this is not a generation with six engines and a maze of transmissions. Shopping well comes down to build date, maintenance evidence, body-specific equipment, and a focused inspection. A documented 2021 or newer car with the S Sport package is the uncomplicated target. A cheaper 2018 can still be worthwhile, but only after a specialist has checked the valvetrain and cooling system.

This Generation at a Glance

Audi launched the US-market B9 S5 for 2018 on the MLB Evo platform. The two-door Coupe arrived alongside the Cabriolet, while the five-door Sportback brought a large rear hatch and a long cargo floor. All three share the longitudinal EA839 3.0 TFSI V6 and ZF eight-speed automatic. There was no US manual and no dual-clutch transmission in this generation.

The owner community calls the 2020 refresh B9.5. Audi revised the front and rear styling and replaced the console-controlled infotainment display with a 10.1-inch MIB3 touchscreen. Output was listed at 354 hp for early US cars and 349 hp after the refresh, with 369 lb-ft of torque throughout. The small published horsepower change did not create a materially different powertrain.

Body style matters more. The Sportback has four conventional doors, a liftback, and the best rear-seat access. The Coupe has the cleanest proportions and a conventional trunk. The Cabriolet trades roof-up quietness and cargo room for an insulated power soft top. All use quattro, but the desirable S Sport package adds the torque-vectoring sport rear differential, adaptive dampers, and red brake calipers. Audi and Car and Driver both identify that differential and damper package as the option that gives the S5 its sharper chassis behavior.

Current inventory can be compared on the Audi S5 market page. Verified year pages are available for 2018, 2019, 2021, 2022, 2023, and 2024. The 2020 page was not available when this guide was prepared, so it is intentionally not linked.

Powertrain and Known Problems

2018-2019 EA839 3.0T V6

The early 3.0 TFSI is quick, smooth, and generally tolerant of high mileage when serviced, but its rocker arms are the generation's largest financial risk. Community parts research on Audizine and r/AudiS4 places the final revised rocker design in production during 2018. That makes a model-year cutoff unreliable. Some 2018 cars have the earliest design, while owners have documented early-build 2019 cars that may still carry it.

The warning is a distinct metallic tick from the top of the engine that rises with rpm. Direct injectors make a normal fast sewing-machine sound, so an unfamiliar buyer should not diagnose this by ear in a parking lot. Ask an Audi specialist to listen from cold, inspect the oil filter for metal, and use a borescope where practical. A verified build date after the revised parts entered production reduces uncertainty, but service invoices or direct inspection are stronger evidence than the VIN year alone.

Failure frequency is not known. Forums contain both old-design engines that have passed 100,000 miles and expensive failures below that point. One EA839 owner report put a cam-and-rocker repair at a $6,000 minimum, while complete engine damage can move the bill into five figures. VAG Technic's current preventive replacement service is priced at £3,950 in the UK, which illustrates the labor involved even before any damaged camshaft or cylinder head is found.

Cooling-system trouble is less dramatic but more common in owner discussions. The mechanical water pump can leak into its vacuum chamber rather than leaving a simple puddle. NGP Racing's technical guide explains that coolant may then migrate through vacuum lines into control solenoids. Symptoms include a falling reservoir level, a sweet smell, overheating warnings, or a P0299 underboost code after contaminated vacuum components stop working correctly.

An Audizine S5 owner described topping up coolant every three or four days before replacing the pump, thermostat, and shutoff valve. Another owner reached 101,000 miles before a water-pump repair. Those examples show why mileage is not a reliable filter. A pressure test, vacuum-line inspection, and repair invoice identifying exactly which parts were replaced are more useful than an assurance that the reservoir was merely topped off.

The PCV assembly is another repeat item. A failed separator can cause whistling, excessive crankcase vacuum, rough idle, oil consumption, or mixture faults. Parts kits currently range from roughly $130 to $330 before labor, according to ECS Tuning, but access and diagnosis make the installed bill higher. Oil around the filter housing should also be traced carefully. One Audizine owner was quoted about $7,000 for a rear main seal before finding that an oil-filter-housing repair addressed the leak for a small fraction of that figure.

2020-2024 EA839 3.0T V6

The facelift engine keeps the same basic architecture, turbocharger layout, torque output, and ZF automatic. It also avoids the early rocker-arm uncertainty for a normal unmodified car. That does not make it maintenance-free. Water-pump, vacuum-control, PCV, engine-mount, and suspension complaints continue in B9.5 owner threads. A 2022 owner on r/audis5 reported water-pump and vacuum-system replacement around 49,000 miles, while several 2021 and 2022 owners report no engine problems at similar mileage.

Active hydraulic engine mounts deserve their own check. Failed mounts can leak fluid, store a fault code, or transmit vibration into the seat and steering wheel at idle. Audizine's Stage 3 owner log recorded mounts at 59,000 miles. Independent cost discussions commonly land around $1,500 to $2,000 for both sides, depending on labor rate, while RepairPal's broader S5 estimate is lower at $921 to $1,130. Scan for mount-control faults even when the cabin feels smooth because a seller can clear codes shortly before a showing.

Front upper control-arm bushings often announce themselves with a clunk over broken pavement, vague steering, or uneven inner-edge tire wear. One long-term owner replaced bushings around 69,000 miles. Another r/audis5 buyer was quoted $6,700 for a bundle covering a water pump, engine mounts, and control arms. The bundle is not a universal price, but it shows how several ordinary B9 jobs can erase the apparent savings on a neglected car.

The ZF eight-speed and quattro system are not leading failure themes in the source set. They still need evidence of care. A slight low-speed pause or a firm second-gear shift in a cold transmission can be characteristic; flares, repeated thumps, delayed engagement, or driveline vibration are not. Enthusiast owners commonly service transmission and transfer-case fluids around 40,000 to 60,000 miles even though factory schedules and dealer advice vary. Modified cars deserve extra scrutiny because the EA839 responds easily to software, and a returned-to-stock ECU does not undo hard launches or skipped fluid service.

Trim Levels

Audi changed packaging during the run, so equipment should be confirmed from the original window sticker rather than inferred from a badge. Early 2018 cars were primarily Premium Plus or Prestige. Premium later became the entry trim, with Premium Plus and Prestige above it. Appearance packages and Black Optic cars are common, but they do not substitute for the chassis or safety options.

The S Sport package is the option to prioritize. The standard car is secure and fast, but owners repeatedly describe the sport differential as the feature that makes the chassis rotate under power instead of simply gripping. The package's adaptive dampers also widen the difference between daily comfort and a back-road setting. Red calipers are an easy visual clue, not proof. Decode the build sheet because calipers can be painted and wheels can be changed.

Prestige adds useful technology, especially the head-up display, top-view camera, acoustic front glass, ambient lighting, and stronger driver-assistance suite cited by AudiWorld and Audizine owners. It also adds systems that are expensive to diagnose after collision repairs. Premium Plus with S Sport is usually the sweet spot. Choose Prestige when its specific features matter and every camera, radar sensor, light, and windshield-mounted component works without stored faults.

For body styles, inspect different things. Coupe buyers should operate the long front seats and check rear-seat entry. Sportback buyers should test the powered hatch, parcel cover, rear wiper, and cargo-area water seals. Cabriolet buyers should cycle the roof twice, examine the fabric and rear glass bond, check the drains, and listen for wind noise after the latches pull tight. Water staining under carpets or in the trunk is a reason to pause, not a detailing issue.

Which Model Years to Target Within This Generation

The year table uses NHTSA's vehicle and campaign databases for recall counts. Counts are not a reliability score, and a zero does not guarantee that every service action is complete. Run the exact VIN because body style, build date, and equipment can change campaign eligibility.

The 2018 model year had two verified NHTSA campaigns. Campaign 19V547000 addressed oxidation at a passenger occupant-detection cable, and 21V874000 covered a seat-heater cable contact that could disable the passenger airbag on affected 2018-2020 S5s. The 2019 model year also included campaign 19V114000 for front shock-absorber forks that could crack on certain Cabriolets and Sportbacks.

Rear suspension and camera campaigns account for several later-year counts. Campaign 21V295000 covered a rear trailing-arm lock nut vulnerable to stress corrosion on specified 2019-2021 S5 bodies. Campaign 22V034000 required a rear alignment inspection on specified 2019-2021 cars after an earlier remedy. Camera campaigns 20V737000, 21V825000, 22V742000, and 22V806000 apply to particular years or body styles, not every S5 in the table. Campaign 24V251000 covers the passenger occupant-detection connection on certain 2023 S5 Cabriolets and Sportbacks.

The recommendation is therefore mechanical, not based on the smallest recall number. A 2021 or 2022 Premium Plus Sportback with S Sport, original software, complete fluid history, and a clean specialist inspection is the broadest sweet spot. The 2020 offers much of the same package for less. A late-build 2019 can be compelling when its rocker hardware is documented, but it should not command the same confidence merely because the listing says one owner.

Pre-Purchase Inspection Checklist

Start with the car fully cold. Ask the seller not to warm it before the appointment, then confirm coolant and oil temperatures on startup. Listen at both cylinder heads for a slow, sharp metallic tick that stands apart from the rapid injector chatter. If the sound is ambiguous on a 2018 or early 2019, stop guessing and arrange a borescope or valvetrain inspection with an Audi specialist.

1. Confirm build data and software history. Get the original window sticker, build month, service records, and a scan report. Look for evidence of ECU or transmission tuning, then evaluate the car as modified even if the current software is stock.
2. Pressure-test the cooling system. Inspect the water pump, thermostat area, reservoir level, vacuum hoses, and control solenoids for dried pink residue or migrated coolant. Scan for underboost and cooling faults.
3. Inspect the oil filter and leaks. Cut open the old filter if the seller authorizes it and look for metallic debris. Trace oil around the filter housing and rear of the engine rather than accepting an instant rear-main-seal diagnosis.
4. Test PCV function. Listen for whistling, watch idle quality, check crankcase vacuum, and review oil-consumption history. A recently cleaned engine bay makes leakage harder to judge.
5. Scan the active mounts and chassis systems. Check for mount-control, adaptive-damper, dynamic-steering, sport-differential, camera, and radar faults with a VAG-capable tool.
6. Load the suspension. Drive over small sharp bumps, brake firmly from neighborhood speed, and inspect inner tire shoulders. Clunks, steering wander, or feathered wear point toward bushings, alignment, or collision damage.
7. Exercise the driveline. Test cold and warm shifts, reverse engagement, full-lock turns, and moderate acceleration. Look for flares, bangs, shudder, or a center-driveline vibration.
8. Measure brakes and tires. S5 brakes and 19- or 20-inch tires are consumables with four-figure replacement potential. Mismatched tire brands or tread depths can also stress an AWD system.
9. Inspect the body-specific systems. Cycle a Sportback hatch, Coupe seat mechanisms, or Cabriolet roof and drains. Check under carpets, spare-wheel wells, and side trim for water.
10. Verify safety campaigns by VIN. Run every car through the recall lookup. Ask for completed-remedy documentation only after the VIN result shows the campaign applies.

A clean generic OBD scan is not enough. The inspection should use a VAG-capable scanner that can reach every control module and show readiness status, stored history, and recently cleared faults. On a Prestige car, that includes cameras, parking sensors, adaptive cruise hardware, head-up display, and lighting modules. On an S Sport car, it includes the rear differential and dampers.

Running Costs

The S5 can deliver mid-20s fuel economy on a gentle highway trip, but its repair budget belongs to a German performance car. EPA combined ratings span roughly 22 to 24 mpg depending on body and year. It requires premium fuel, carries staggered or wide performance tires on many builds, and often needs alignment work to protect the inner shoulders.

These are planning ranges, not quotes. Current parts pricing, local labor rates, wheel size, and the damage found during diagnosis can move them substantially. The high cooling figures include owner allegations summarized in litigation reporting about EA839 water pumps; they should not be treated as a universal dealer price or a finding that every pump will fail.

For a car outside warranty, keep a repair reserve of at least $2,000 beyond routine tires, brakes, fuel, registration, and insurance. That figure will not cover an engine failure, but it prevents an engine mount or cooling repair from becoming deferred maintenance. An early car without credible rocker evidence needs a larger contingency or a lower purchase price that genuinely reflects the risk.

Service history should show regular oil changes, brake-fluid changes, plugs at an appropriate interval, and attention to transmission and differential fluids. Audi's official schedule is the baseline, not proof that every fluid remains lifetime-fresh under tuned or hard use. A thick folder from a reputable independent specialist is worth more than a low odometer with missing years.

FAQ

Is the B9 Audi S5 reliable?

The B9 S5 can be reliable when stock and maintained, but it is not low-risk transportation. Cooling-system leaks, PCV assemblies, active engine mounts, and front control-arm bushings recur across owner reports. Early rocker arms add a rare but severe engine risk. Later cars reduce that uncertainty, though they still need a specialist inspection and repair reserve.

Which B9 Audi S5 model year is best?

The 2022 S5 is the best all-around target. It has the B9.5 touchscreen and revised early-engine hardware, while avoiding the price premium attached to the newest examples. A 2021 is also strong after VIN recall verification. Equipment matters: a Premium Plus with the S Sport package is usually more rewarding than a Prestige without it.

Should I avoid every 2018 Audi S5 because of rocker arms?

No, but a 2018 should never be bought on model year and service stamps alone. The community's parts research places rocker revisions during 2018 production, and old-design cars can survive high mileage. Verify build information, listen from cold, inspect the oil filter, and use a specialist or borescope when uncertainty remains. Price the residual risk honestly.

Is the S5 Sportback more expensive to maintain than the Coupe?

Their engine, transmission, AWD system, brakes, and core suspension are substantially shared, so routine mechanical costs are similar. The Sportback adds rear doors, hatch hardware, a rear wiper, and extra seals. The Coupe adds long power-seat mechanisms. Condition and option content usually affect the bill more than choosing between these two bodies.

Is the S Sport package worth finding?

Yes for most enthusiast buyers. Its torque-vectoring rear differential changes how the S5 puts power down in a corner, and the adaptive dampers improve the useful range between comfort and control. Verify the package through the build sheet and scan its modules. Red calipers alone do not prove that the original differential and dampers are present.

Bottom Line

The B9 Audi S5 is at its best as a 2021 or 2022 Premium Plus with the S Sport package, original software, and complete specialist records. The Sportback offers the most utility, while the Coupe and Cabriolet preserve the same strong drivetrain in more emotional shapes. Always check the cooling system and active mounts, and never treat an early car's rocker-arm risk as an internet myth simply because it sounds quiet after the seller warmed it.

Run every VIN through a recall check. CarScout members can track daily price and inventory changes for the exact body, trim, and year they want from the Audi S5 market page, with one email digest each day.

Data sourced from the NHTSA recalls database, EPA fuel economy data, Audi USA model releases, Car and Driver testing, Kelley Blue Book consumer reviews, RepairPal estimates, ECS Tuning parts listings, NGP Racing technical guidance, VAG Technic service information, and real owner experiences from Audizine, AudiWorld, r/audis5, r/AudiS4, and r/Audi. See the full Audi S5 market data for pricing and inventory.