A rally-bred icon beloved by enthusiasts for its raw driving experience and all-wheel-drive performance. The EJ257 engine is a tuner favorite but comes with significant risks: ringland piston failure is semi-common even on stock cars, especially when driven hard or with insufficient warm-up. The 6-speed manual is strong, but clutches wear quickly under aggressive use. Most failures trace back to modifications and improper tuning—stock cars maintained properly can exceed 150,000 km. 2019+ models received stronger pistons and slightly improved reliability. Critically: check modification history, confirm all recalls completed, and avoid cars with aftermarket tunes unless professionally documented.
Expected Annual Maintenance Costs
€1,200 - €2,100/year
15,000 km/year
Fixed costs
€650-950
Risk buffer
€550-1,150
What Can Break
bars = likelihood
Ringland piston failure€4,500 - €10,000
Piston ring groove cracks under heat and stress, causing catastrophic engine damage · more· less
The EJ257's cast hypereutectic pistons are known for ringland failures. The primary compression ring gap is too tight from factory, causing the ring to bind when heated. Under load, this creates point stress on the ringland (the area between ring grooves) which cracks or breaks entirely. Symptoms include blue/white smoke, loss of compression on cylinder 4, rough idle, and loss of power. Common triggers: engine knock from poor fuel, hard acceleration below 3,500 RPM (lugging), insufficient warm-up, or aggressive tuning. A short block rebuild with forged pistons costs €4,500-6,000 in parts and labor. Full engine rebuild runs €7,000-10,000. 2019+ models have updated pistons that reduce (but don't eliminate) this risk. Prevention: always warm engine fully before boost, use premium fuel, avoid lugging, and run conservative tunes.
Turbocharger failure€2,500 - €4,000
Factory IHI turbo fails typically between 100,000-125,000 km due to heat and wear · more· less
The stock IHI turbocharger runs at extremely high speeds (150,000+ RPM at peak boost) and is subjected to intense heat cycles. Common symptoms: blue smoke from exhaust, loud whining noise, oil in intercooler or intake piping, loss of boost pressure. Failure accelerates dramatically when tuned for higher boost. OEM replacement turbo costs €2,000-2,500, plus €500-1,000 labor. Upgraded aftermarket turbos (Blouch, GrimmSpeed, Forced Performance) cost €2,500-4,000 installed and are more durable. Oil starvation from missed oil changes is a major cause of premature failure. Always replace turbo oil feed and return lines during turbo replacement to prevent repeat failures.
Clutch wear and replacement€1,200 - €2,500
Stock clutch lasts 40,000-80,000 km with normal use, much less if launched hard · more· less
The 6-speed manual transmission is strong, but the clutch is a wear item that requires regular replacement on performance cars. STI clutches experience high load due to AWD drivetrain losses and sticky summer tires. Symptoms of worn clutch: slipping under acceleration (especially in high gears), burning smell, difficulty engaging gears, high engagement point. OEM clutch kit costs €600-800, labor is €500-700 (5 hours). Upgraded performance clutches (ACT, Exedy, Competition Clutch) cost €800-1,500 depending on stage, providing better grip and longer life but often with heavier pedal feel. If flywheel surface is damaged, resurfacing adds €50-100 or replacement adds €200-400. Budget €1,200-1,500 for basic clutch job, €1,800-2,500 with upgraded clutch and flywheel.
Head gasket failure€1,500 - €3,500
Less common on turbo models than NA Subarus, but overheating or detonation can cause failure · more· less
While turbocharged Subarus have fewer external head gasket leaks than naturally aspirated models, internal head gasket failures do occur from overheating, sustained high boost, or detonation. Symptoms: white smoke from exhaust, coolant mixing with oil (milky oil), overheating, loss of coolant with no visible leak. Root causes include cooling system failures (radiator, thermostat, water pump), sustained high boost on poor fuel, or peripheral issues like blocked radiator cores. Labor time is 13-15 hours. Parts (gasket kit, ARP head studs, timing components) cost €800-1,200, labor €1,500-2,000, total €2,300-3,200. Often combined with timing belt service to save labor. If head is warped from overheating, machining adds €200-400 or replacement €800-1,500. On turbocharged models, a blown head gasket often indicates other engine damage requiring full rebuild.
Valve cover gasket oil leaks€300 - €600
Gaskets degrade after 8+ years or 100,000+ km, causing external oil leaks · more· less
The boxer engine's horizontal layout means valve covers are on the sides of the engine. Valve cover gaskets deteriorate over time from heat cycling, causing oil to seep down the sides of the engine block. Look for oil residue on the engine sides or oil dripping onto the exhaust manifold (creates burning oil smell). Gasket kits cost €30-60 for both sides including spark plug tube seals. Labor is 2-3 hours per side, €250-400 total. This is a straightforward repair but requires removing intake components for access. If oil has been leaking onto spark plug tubes, ignition coils may also need replacement. Not an urgent repair if leaking is minor, but should be addressed before oil reaches hot exhaust components.
Spark plugs and ignition coils€350 - €900
Turbo engines burn through plugs and coils quickly, need replacement every 30,000-50,000 km · more· less
High cylinder pressures from turbocharging rapidly degrade spark plugs. Symptoms of worn plugs: misfires (especially under boost), rough idle, hesitation, check engine light (codes P0301-P0304). OEM spark plugs (NGK or Denso one-step colder for performance) cost €8-15 each (€32-60 for set of 4). Ignition coils fail less frequently but valve cover gasket oil leaks can damage them. Coil failure symptoms: persistent misfire on one cylinder, loss of power. OEM coils cost €80-120 each. Labor for spark plug replacement: €100-150 (1.5 hours). If coils also need replacement, add €150-250 labor. Total for plugs and 1-2 failed coils: €350-600. Full coil pack replacement (all 4): €750-900. Tuned cars should use one-step-colder plugs and replace more frequently (every 20,000 km).
Wheel bearings€350 - €800
AWD system and sticky tires cause higher bearing wear, typically 80,000-120,000 km · more· less
The STI's performance AWD system and aggressive alignment settings place higher loads on wheel bearings than typical cars. Symptoms: humming or grinding noise that increases with speed, steering vibration, pulling to one side. Rear bearings tend to fail first. OEM wheel bearing/hub assemblies cost €150-250 each, labor €150-300 per wheel (2-3 hours). Total per wheel: €300-550. At high mileage (100,000+ km) it's advisable to replace both bearings on the same axle to prevent near-future repeat work. Front bearings are slightly more labor-intensive due to ABS sensor and brake components. Use OEM or quality aftermarket (Timken, SKF, NSK) for reliability.
Brake pads and rotors (Brembo)€600 - €1,500
Performance Brembo brakes wear faster, pads every 30,000-50,000 km, rotors every 60,000-100,000 km · more· less
The STI comes with high-performance 4-piston Brembo brakes (front: 326mm, rear: 316mm). While extremely capable, they use performance pads that wear faster than economy car brakes. Front pads wear quicker due to weight transfer during braking. OEM Brembo pads: €150-200 per axle, aftermarket performance pads (Hawk HPS, EBC Yellowstuff): €100-180 per axle. Rotors: OEM €200-300 per pair, aftermarket slotted €180-250. Labor for pads: €100-150, for pads and rotors: €200-300. Typical brake service (front pads): €300-400. Full 4-wheel pads and rotors: €1,200-1,500. Aggressive driving or track use doubles wear rates. Brake fluid should be changed every 2 years (€100-150) to prevent moisture absorption and fade.
Clutch pedal issues and throw-out bearing€150 - €1,500
2015+ models suffer from pedal creaking, inconsistent engagement point, and TOB failures · more· less
Common issues on 2015-2021 VA models: creaking or gritty clutch pedal feel (TSB 03-82-18 addresses this with updated release bearing grease), low or high engagement point requiring adjustment, knocking/popping sound during clutch travel, and squeaking pedal. Most are minor and fixable with adjustment or lubrication (€50-150 at shop). More serious: throw-out bearing failure where the bearing ears crack or bend, causing rattling before complete failure and pedal dropping to floor. If TOB fails, transmission must be removed for replacement—labor overlaps with clutch job so typically both are done together (€1,200-1,800). DIY fixes exist for pedal noise (washer between pedal assembly and firewall, greasing actuator rod) but professional inspection recommended if symptoms worsen.
Fuel injector failures and cleaning€400 - €1,200
Injectors clog or fail electrically after 50,000-100,000 km depending on fuel quality · more· less
Symptoms of failing injectors: rough idle, misfires, hesitation, poor fuel economy, fuel smell, check engine light. Direct-injection turbocharged engines are sensitive to fuel quality. Poor fuel causes carbon buildup and clogging. Best practice when one injector fails: remove and service all four simultaneously to balance flow rates. Professional ultrasonic cleaning service: €200-350 for all four. If electrically failed, OEM injectors cost €80-150 each (€320-600 for set). Labor to remove/replace: €150-300. Total for cleaning: €400-600. Total for replacement: €750-1,200. Preventive maintenance: use premium fuel, add injector cleaner every 5,000 km, replace fuel filter per schedule. Tuned cars with upgraded injectors less prone to issues if properly sized.
High-risk ownership, but manageable with proper care
The WRX STI is an enthusiast's car with enthusiast-level maintenance costs and risks. The biggest threat is ringland failure, which can total the engine. However, stock, well-maintained examples with proper warm-up and quality fuel are reasonably reliable. The critical variables: modification history (avoid poorly tuned cars), maintenance records (oil changes every 5,000 km crucial), and driving style (avoid lugging, always warm up fully). 2019+ models with updated pistons are slightly safer. Budget significantly more than a mainstream performance car.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete records essential, especially oil changes every 5,000 km maximum. Verify timing belt replaced at intervals.
Tires
Check 245/40R18 tread depth and age. Uneven wear indicates alignment or suspension issues common on lowered cars.
Cold start
Engine must start completely cold. Listen for rattles, ticking, or smoking. Blue/white smoke indicates ringland failure.
Test drive
Minimum 30 minutes including hard acceleration in 2nd and 3rd gear after full warm-up. Watch for smoke under boost.
Body condition
Check for accident damage. Many STIs have been tracked or autocrossed—undercarriage damage is common.
Specific for this vehicle
Compression and leak-down test mandatory
Do NOT buy without professional compression test. Cylinder 4 most prone to ringland failure. All cylinders should read 140-160 PSI within 10% of each other. Leak-down test should show less than 10% loss per cylinder.
Check for modification history
Ask directly: any aftermarket tune? Upgraded turbo? Intake/exhaust/downpipe? Request dyno sheets and tuner documentation. Avoid cars with tunes from unknown sources. Check for AccessPort or other tuning devices.
Look for oil leaks on engine sides
Boxer engines leak from valve covers. Check entire engine perimeter for oil residue. Oil on exhaust manifolds creates burning smell.
Inspect turbocharger for shaft play and oil leaks
Remove intake pipe and wiggle turbo shaft—minimal play acceptable. Check intercooler piping and intake for oil (indicates turbo seal failure).
Test clutch engagement point and pedal feel
Engagement should be consistent and smooth. Slipping under hard acceleration in high gear indicates worn clutch. Listen for rattling when depressing clutch (throw-out bearing).
Check for knock/detonation with AccessPort or OBD scanner
If seller has AccessPort, monitor knock correction values during test drive. Sustained negative values indicate engine knock (serious issue). Ask seller to demonstrate no check engine lights in hidden menus.
Verify all recalls completed (especially backup lamp switch)
2015-2021 backup lamp switch recall critical. Check VIN with Subaru dealer for any open recalls or TSBs.
Listen for transmission gear grinding
Test all gears during drive. 2nd gear synchro most prone to wear. Grinding when shifting indicates synchro damage or clutch issues.
Check for wheel bearing noise
Listen for humming that increases with speed. Test at 80-100 km/h. Rear bearings fail more often. Turn steering left and right—noise changing indicates which bearing.
Inspect brake pads, rotors, fluid condition
Brembo brakes are expensive. Measure pad thickness (replace below 3mm). Check rotors for scoring or cracks. Brake fluid should be clear, not brown (indicates overdue change).
Various TSBs for audio/Starlink system (2015+)Software updates available
Contact Subaru dealer with VIN to verify all recalls and TSBs completed. The backup lamp switch recall affects safety and should be confirmed. Clutch pedal TSB is a common quality-of-life improvement.
Warranty Status
Factory warranty (3 years/100,000 km)Expired on all 2014-2021 models
Powertrain warranty (5 years/100,000 km)Expired on most models
Extended warranty (if purchased)Check with seller/dealer
All 2014-2021 WRX STIs are outside factory warranty coverage. Extended warranties for STI models cost significantly more (€300-500 premium) due to turbocharged engine risks. Some aftermarket warranty providers exclude modified vehicles entirely—verify coverage details before purchase.
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.