The 2005 Impreza with the 2.5L EJ25 is generally reliable but notorious for head gasket failure, a platform-wide weakness that can cascade into catastrophic engine damage if ignored. These cars can run 200,000+ miles if the head gaskets are addressed proactively.
Head Gasket Failure (External Oil/Coolant Leaks)
Common · high severityTypical onset: 80,000-120,000 mi
Symptoms: Oil seepage around cylinder heads, visible on engine block, Coolant smell from engine bay, slow coolant loss without visible external leaks, White residue on oil cap or dipstick (coolant mixing with oil), Overheating if coolant loss progresses unchecked
Fix: Both head gaskets must be replaced; machine shop resurface of heads recommended. Timing belt, water pump, tensioners, and all coolant hoses should be done simultaneously since engine is apart. 12-16 labor hours total.
Estimated cost: $2,000-3,200
Piston Ringland Failure / Spun Rod Bearings
Occasional · high severityTypical onset: 100,000-150,000 mi
Symptoms: Sudden loss of power, misfires on one cylinder, Metallic knocking or rattling from engine block, Compression loss on one or more cylinders, Check engine light with misfire codes (P0301-P0304)
Fix: Catastrophic internal engine damage. Most shops recommend short block replacement or used engine swap rather than rebuild due to labor costs. 18-24 labor hours for short block R&R.
Estimated cost: $3,500-5,500
Transmission Oil Cooler Line Corrosion (Automatic only)
Common · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Transmission fluid leaking from front of vehicle near radiator, Low transmission fluid warning or slipping gears, Pink fluid spots on driveway, Delayed engagement in Drive or Reverse
Fix: Replace corroded steel cooler lines with updated parts (OEM or aftermarket stainless). Flush transmission fluid and inspect for contamination. 2-3 labor hours.
Estimated cost: $300-600
Front Lower Control Arm Bushing Failure
Common · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Clunking noise from front suspension over bumps, Steering wander or poor alignment retention, Uneven front tire wear (inner or outer edge), Steering wheel off-center after alignment
Fix: Replace front lower control arms (bushings are not serviced separately on most aftermarket parts). Alignment required after installation. 2-3 labor hours plus alignment.
Estimated cost: $400-700
Fuel Filter Clogging (High-Mileage Vehicles)
Occasional · medium severityTypical onset: 120,000+ mi
Symptoms: Hard starting, especially when hot, Loss of power under acceleration or at highway speeds, Engine stumbling or hesitation, Check engine light with fuel trim codes
Fix: In-tank fuel filter (part of fuel pump assembly) requires dropping fuel tank. Many shops replace entire pump assembly due to access difficulty. 2-3 labor hours.
Estimated cost: $400-800
Timing Belt and Water Pump Failure
Occasional · high severityTypical onset: 90,000-110,000 mi
Symptoms: Coolant leak from water pump weep hole, Squealing or grinding noise from timing cover area, Engine will not start if belt breaks (interference engine), Overheating due to failed water pump
Fix: Replace timing belt, tensioners, idlers, and water pump as a kit. EJ25 is interference; belt failure destroys valves and pistons. 4-6 labor hours if caught before failure.
Estimated cost: $800-1,200
Front Oxygen Sensor Failure
Occasional · low severityTypical onset: 100,000-150,000 mi
Symptoms: Check engine light with P0420 or P0131/P0137 codes, Rough idle or poor fuel economy, Failed emissions test, Sluggish throttle response
Fix: Replace upstream O2 sensor(s). Subaru OE sensors strongly recommended; aftermarket often cause repeat codes. 0.5-1 labor hour per sensor.
Estimated cost: $200-400
Buy one if head gaskets are documented as done and engine compression tests clean; avoid high-mileage examples with unknown maintenance history — the $3,000 repair lottery isn't worth it.
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.