The 2012 WRX STI is a high-strung performance machine built around the legendary EJ257 boxer engine. It's bulletproof when maintained religiously, but becomes expensive quickly when abused or neglected—and many have been driven hard.
EJ257 Ringland Failure (Piston #4)
Occasional · high severityTypical onset: 60,000-100,000 mi
Symptoms: misfires on cylinder 4, loss of compression, white/blue smoke under boost, check engine light with P0304 code, oil consumption increases dramatically
Fix: Complete engine rebuild or replacement. Requires removing engine, machining block, replacing pistons with forged units, new rings, bearings, head work. 25-35 labor hours. Most opt for built shortblock and upgrade while they're in there.
Estimated cost: $6,000-12,000
Turbocharger Failure (IHI VF48)
Common · high severityTypical onset: 80,000-120,000 mi
Symptoms: blue smoke on startup or acceleration, whining or grinding noise from turbo, oil in intercooler piping, loss of boost pressure, P0299 underboost code
Fix: Replace turbocharger assembly. Turbo removal requires dropping the engine or extensive top-side disassembly. 8-12 labor hours. Critical to diagnose why it failed—often oil starvation from neglected changes or banjo filter clogging. Always replace oil feed/return lines.
Estimated cost: $2,500-4,000
Transmission Synchro Wear (1st and 2nd Gear)
Common · medium severityTypical onset: 70,000-110,000 mi
Symptoms: grinding when shifting into 1st or 2nd, difficulty engaging gears when cold, gear pop-out under load, notchy shifting even with fresh fluid
Fix: Transmission rebuild with new synchros, shift forks inspection, bearings as needed. Trans must come out—8-10 hours removal/install, plus internal rebuild time. Many upgrade to STI 6-speed refresh kit while in there.
Estimated cost: $3,000-5,500
Timing Belt and Water Pump (Interference Engine)
Common · high severityTypical onset: 105,000 mi or 105 months
Symptoms: this is preventive—if belt breaks, you have bent valves and destroyed engine, squealing from belts area if idler bearings failing
Fix: Replace timing belt, all idlers, tensioner, water pump, camshaft and crankshaft seals as preventive service. Not if-but-when maintenance. 6-8 labor hours. Skip this and you're looking at head removal and valve work minimum.
Estimated cost: $1,200-1,800
Transmission Mount Failure (Pitch Stop Mount)
Common · low severityTypical onset: 50,000-80,000 mi
Symptoms: clunking during hard acceleration or deceleration, excessive engine/trans movement felt through shifter, vibration at idle in gear
Fix: Replace rear transmission mount (pitch stop). Simple job, 1-2 hours. Most owners upgrade to stiffer aftermarket units which last longer but increase NVH slightly.
Estimated cost: $200-400
Banjo Bolt Filter Clogging (Turbo Oil Feed)
Occasional · high severityTypical onset: any mileage if oil changes neglected
Symptoms: turbo failure due to oil starvation, smoking turbo, turbo bearing noise, often discovered post-turbo-failure during diagnosis
Fix: Preventive removal and inspection of banjo bolt filters during oil changes, especially if car has unknown history. 0.5 hours when done proactively. Many techs remove them entirely after inspection if debris found, ensuring adequate oil flow. Reactive fix means you're already replacing the turbo.
Estimated cost: $50-100 preventive / $2,500+ if turbo already damaged
AVCS Cam Position Sensor Failures
Occasional · medium severityTypical onset: 80,000-130,000 mi
Symptoms: check engine light with P0011 or P0021 codes, rough idle when warm, hesitation or bucking under light throttle, reduced power
Fix: Replace intake and/or exhaust cam position sensors. Access isn't terrible on these—2-3 hours. Sometimes related to oil control valve failures as well, which should be tested during diagnosis.
Estimated cost: $400-700
Buy one only if you can verify meticulous maintenance history and accept that performance car ownership means expensive, frequent service—this is not a Corolla.
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.