The 2006 Forester XT shares the EJ255 turbocharged engine with the WRX—quick and fun, but notorious for head gasket failures, ringland cracks, and transmission weaknesses under spirited driving. Budget for major engine work if buying high-mileage.
Head Gasket Failure (External Leaks)
Common · medium severityTypical onset: 80,000-120,000 mi
Symptoms: oil seepage at block/head interface visible from below, coolant smell after shutdown, slow coolant loss without visible external drips, oil spots on driveway
Fix: Both head gaskets, resurfacing if needed, timing components while in there. 12-16 hours labor. Many shops do timing belt, water pump, all seals as a package since engine is apart.
Estimated cost: $2,200-3,500
Ringland Failure (Piston #4)
Occasional · high severityTypical onset: 60,000-100,000 mi
Symptoms: cylinder 4 misfire code (P0304), excessive blowby and oil consumption (1qt per 500mi), rattling noise on cold start, loss of boost pressure, white/blue smoke from exhaust under load
Fix: Ring lands crack on #4 piston from detonation or overboosting. Requires engine removal, short-block replacement or full rebuild with forged pistons. 20-30 hours labor depending on shop workflow.
Estimated cost: $4,500-7,500
Turbocharger Failure
Occasional · high severityTypical onset: 100,000-140,000 mi
Symptoms: loud whine or whistle under boost, blue smoke on startup or deceleration, loss of power above 3000 RPM, shaft play in compressor wheel, oil pooling in intercooler
Fix: IHI VF40 turbo fails from oil starvation or bearing wear. Replace turbo, all oil feed/return lines, engine oil and filter. 6-8 hours labor. Upgraded turbos common at this point.
Estimated cost: $1,800-3,200
Transmission Failure (4EAT Automatic)
Common · high severityTypical onset: 120,000-160,000 mi
Symptoms: delayed or harsh 2-3 shift, slipping under throttle, whining noise in gear, burnt ATF smell, check engine light with trans codes
Fix: The 4EAT behind the turbo is marginal—torque converter, clutch packs, and valve body all wear. Rebuild or reman unit. 10-14 hours labor for R&R and setup.
Estimated cost: $2,800-4,500
Transmission Oil Cooler Line Leaks
Common · medium severityTypical onset: 90,000-130,000 mi
Symptoms: ATF puddle under engine bay passenger side, low trans fluid warning, burnt fluid smell, transmission slipping or overheating
Fix: Hard lines rust through or rubber sections crack at crimps. Replace cooler lines and top off ATF. 2-3 hours labor. Inspect radiator end-tank trans cooler for cross-contamination if lines failed internally.
Estimated cost: $350-650
Crank Position Sensor Failure
Occasional · high severitySymptoms: no-start when hot, restarts when cool, intermittent stalling at idle, tachometer dropping to zero while driving, P0335 crank sensor code
Fix: Sensor behind timing cover fails from heat cycles. 3-4 hours labor because you're removing accessories and part of timing covers. Do cam and crank sensors together.
Estimated cost: $450-750
Engine Mounts and Transmission Mount Failure
Common · low severityTypical onset: 80,000-120,000 mi
Symptoms: clunking on throttle tip-in or shifts, excessive engine movement visible from engine bay, vibration at idle, shifter buzz in cabin
Fix: Pitch stop mount (dogbone) and rear trans mount tear from turbo torque. Replace all motor mounts as a set. 3-4 hours labor.
Estimated cost: $600-900
Buy only with full service records and compression test—great driving dynamics, but the drivetrain is a ticking time bomb without meticulous maintenance.
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.