The 2004 WRX is a legendary turbocharged Subaru that rewards enthusiasts willing to maintain it properly, but punishes those who mod aggressively or skip oil changes. Engine internals and head gaskets are the Achilles' heel, especially on cars with unknown modification or maintenance history.
Head Gasket Failure (EJ205 Turbo)
Common · high severityTypical onset: 80,000-120,000 mi
Symptoms: External oil seepage around cylinder heads, White exhaust smoke on cold start, Coolant consumption without visible leaks, Overheating under load
Fix: Both head gaskets, resurface heads, timing belt/water pump while in there, ARP studs recommended. 12-16 hours labor depending on shop efficiency and whether heads need machine work.
Estimated cost: $2,200-3,500
Ringland Failure / Cracked Pistons
Occasional · high severityTypical onset: 60,000-100,000 mi
Symptoms: Sudden loss of power, Loud knock from cylinder 4 (most common), Misfire codes P0304, Excessive blow-by or smoking, Low compression on one cylinder
Fix: Cast pistons crack under detonation (bad tune, low octane, aggressive boost). Requires short block replacement or full rebuild with forged pistons. 18-24 hours labor for short block swap, more for complete rebuild.
Estimated cost: $4,500-7,500
Turbocharger Failure (IHI VF39)
Occasional · medium severityTypical onset: 100,000-140,000 mi
Symptoms: Whining or grinding noise from turbo, Blue smoke on acceleration, Loss of boost pressure, Check engine light with underboost codes, Excessive shaft play
Fix: Oil starvation or age kills the journal bearings. Replace or rebuild turbo, replace oil feed/drain lines, change oil. 6-8 hours labor for turbo replacement.
Estimated cost: $1,200-2,200
Transmission Synchro Wear (2nd/3rd Gear)
Common · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Grinding into 2nd gear when cold, Difficult shifts into 3rd under load, Crunching even with full clutch depression, Worse with aggressive driving or missed shifts
Fix: 5-speed manual (not 6-speed STI trans) has weak synchros. Requires transmission rebuild with upgraded brass synchros. 8-12 hours labor for removal, rebuild, reinstall.
Estimated cost: $2,000-3,200
Transmission Mount Failure
Common · low severityTypical onset: 60,000-90,000 mi
Symptoms: Clunking on shifts or throttle transitions, Excessive drivetrain movement, Vibration through shifter, Visible torn rubber in pitch stop mount
Fix: Pitch stop mount (rear trans mount) tears from spirited driving. Replace with OEM or upgraded polyurethane. 1-2 hours labor, straightforward job.
Estimated cost: $150-350
Banjo Bolt Filter Clogging (Turbo Oil Feed)
Occasional · high severitySymptoms: Turbo whine or failure without warning, No obvious external oil leaks, Happens after long oil change intervals or contaminated oil
Fix: Tiny filter screen in banjo bolt at turbo oil feed clogs, starving turbo of oil. Many techs remove screen entirely during turbo service. Preventive removal takes 30 minutes if turbo is healthy.
Estimated cost: $50-150
Fuel Pump Failure
Occasional · medium severityTypical onset: 90,000-130,000 mi
Symptoms: Stumbling or hesitation under hard acceleration, No-start condition after sitting, Whining noise from fuel tank, Lean codes or fuel pressure drop
Fix: In-tank pump wears out, especially if car is run low on fuel frequently. Drop tank, replace pump assembly. 3-4 hours labor.
Estimated cost: $500-800
Buy it if you find one bone-stock with documented maintenance and a clean Carfax — avoid modded examples unless you're ready for a rebuild.
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.