The 2002 Impreza 2.5L is fundamentally solid but plagued by predictable engine internal failures—head gaskets are the headline, but piston ringland cracks often follow if owners boost or overheat these engines. Transmission cooling issues compound the problem.
Head Gasket Failure (External Coolant Leaks)
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: Coolant seeping from cylinder heads, visible white crusty residue at block/head junction, Slow coolant loss without visible drips on ground initially, Sweet coolant smell after engine heats up, Overheating if ignored long enough
Fix: Both heads off, resurface, new Subaru OEM gaskets (aftermarket fails quickly), timing belt/water pump while apart, thermostat, all coolant hoses. 12-16 labor hours depending on AC and accessibility.
Estimated cost: $1,800-2,800
Piston Ringland Failure (#4 Cylinder)
Occasional · high severityTypical onset: 60,000-120,000 mi
Symptoms: Sudden misfire with CEL, often P0304 (cylinder 4 misfire), Rough idle, loss of power, Compression test shows 30-60 psi on #4 vs 150+ on others, White smoke or excessive blowby if ringlands completely detach
Fix: Short block replacement or full engine rebuild—piston ringlands crack, usually #4. If one fails, #2 often marginal. Used short blocks common, 18-24 hours removal/install, timing components, seals, gaskets. Inspect for scoring before reusing heads.
Estimated cost: $3,200-5,500
Transmission Oil Cooler Line Corrosion (Automatic)
Common · medium severityTypical onset: 100,000+ mi or 15+ years regardless of miles
Symptoms: ATF dripping from radiator area or frame rails, Pink/red fluid pooling under engine bay passenger side, Transmission slipping or delayed engagement if fluid level drops, Coolant-contaminated ATF (strawberry milkshake) if internal cooler fails
Fix: Replace steel hardlines (they rust through at bends) or upgrade to rubber hose conversion. If internal radiator cooler leaks, flush trans immediately, replace radiator. 2-4 hours if just lines, 6-8 if trans flushing or R&R needed.
Estimated cost: $400-1,200
Front Lower Control Arm Rear Bushing Failure
Common · medium severityTypical onset: 70,000-120,000 mi
Symptoms: Clunking over bumps from front suspension, Steering wanders, imprecise turn-in, Inner tire edge wear due to negative camber shift, Visible torn rubber or separated bushing on inspection
Fix: Replace lower control arms (bushings not serviced separately economically). Alignment required after. 2.5-3.5 hours both sides. Note: NHTSA recall covered some VINs—check eligibility first.
Estimated cost: $450-750
Rear Wheel Bearing Failure
Occasional · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Growling or humming from rear, increases with speed, ABS/traction lights if bearing disintegrates and sensor damaged, Wheel play when jacked—grab top/bottom and rock
Fix: Press out hub/bearing assembly, press in new unit—requires bearing press or hub tamer tool. 1.5-2 hours per side. Fronts can fail too but rears more common on this platform.
Estimated cost: $250-400 per side
Fuel Pump Failure (Sudden No-Start)
Occasional · high severityTypical onset: 120,000-180,000 mi
Symptoms: Cranks but won't start, no fuel pressure at rail, Intermittent stalling when hot, restarts when cool, No audible pump prime when key turned to ON, NHTSA recall for some VINs—check service history
Fix: Drop fuel tank or remove rear seat and cut access panel (not factory). Replace pump assembly. 2-3 hours if access panel exists, 4-5 if tank drop required. Use OEM Subaru pump—aftermarket longevity poor.
Estimated cost: $450-850
Buy if head gaskets already done with receipts and no mods; budget $3k-5k for engine work if they haven't—these motors self-destruct predictably but the chassis is robust.
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.