The 2015 Crosstrek with the FB20 2.0L boxer engine is mechanically solid overall, but suffers from the notorious Subaru piston-slap/oil-consumption issue that can escalate to catastrophic engine failure if ignored. Transmission cooler lines and CVT overheating are secondary concerns on higher-mileage units.
Excessive Oil Consumption / Piston Ring Failure (FB20 Engine)
Common · high severityTypical onset: 60,000-120,000 mi
Symptoms: Burning more than 1 qt oil per 1,000-1,200 miles, Blue smoke on cold start or under acceleration, Check engine light P0420 (cat efficiency) from oil fouling, Piston slap noise on cold starts (sounds like marbles rattling)
Fix: Subaru issued TSB 02-157-14R for ring replacement under warranty extension, but most 2015s are out of coverage now. Repair requires engine-out, complete teardown, and piston ring replacement on all four cylinders. Takes 12-16 labor hours if caught early; if oil starvation damages bearings or scores cylinder walls, you're looking at shortblock replacement at 18-22 hours.
Estimated cost: $3,500-6,500
CVT Transmission Oil Cooler Line Leaks
Occasional · medium severityTypical onset: 80,000-140,000 mi
Symptoms: Red ATF puddles under engine bay, driver's side, Burning smell from fluid hitting exhaust, Low CVT fluid level triggers limp mode or slipping, Visible wetness on cooler lines near radiator
Fix: The rubber hoses at the CVT-to-radiator cooler harden and crack. Both lines should be replaced together with OEM parts to avoid repeat failures. Book time 2.5-3 hours including fluid refill and burping procedure. Aftermarket lines fail prematurely—stick with Subaru parts.
Estimated cost: $450-750
Head Gasket Weepage (Early FB20 Units)
Occasional · medium severityTypical onset: 100,000-150,000 mi
Symptoms: Slight coolant seepage at cylinder head mating surface (external), Sweet smell after driving, no visible leaks on ground, Coolant level drops slowly over weeks/months, No overheating or milky oil—external weep only
Fix: The FB20 is much better than the EJ series, but early production units still see minor external head gasket seepage. Requires engine-out or creative in-chassis work depending on shop. 10-14 hours labor. Always do timing components, water pump, and all external seals while you're in there. Not the catastrophic internal failure the EJ25 was famous for.
Estimated cost: $2,200-3,800
Rear Transmission Mount Failure
Common · low severityTypical onset: 70,000-110,000 mi
Symptoms: Clunking on shifts from reverse to drive, Excessive drivetrain movement felt through floor on throttle tip-in, Vibration at idle that worsens under load, Visual inspection shows torn rubber or separated mount
Fix: The rear diff-mounted transmission crossmember mount tears from drivetrain torque. Common on all CVT Subarus of this generation. Replacement is straightforward—support transmission, remove four bolts, swap mount. 1.5 hours. OEM mount is $120-150; aftermarket polyurethane versions stiffen the ride but last longer.
Estimated cost: $250-400
Brake Light Switch Failure (NHTSA Recall)
Occasional · medium severitySymptoms: Brake lights stuck on even with foot off pedal, Push-button start won't disengage (car thinks brake is pressed), Cruise control won't set or cancels randomly, Battery drain if lights stay on overnight
Fix: Recall WTF-15 addressed defective brake light switches that fail in the 'on' position. If not done, switch replacement takes 0.5 hours at the pedal assembly. Check if recall was completed using VIN lookup—many units still haven't had it done. Free at dealer if open recall.
Estimated cost: $0 (recall) or $150-220 if self-pay
CVT Judder/Shudder on Light Acceleration
Occasional · low severityTypical onset: 50,000-90,000 mi
Symptoms: Vibration/shudder between 20-40 mph under light throttle, Feels like driving over rumble strips, Worse when transmission is cold, No codes, no slipping, just annoying vibration
Fix: Often resolved with CVT fluid flush using Subaru High Torque fluid (do NOT use generic CVT fluid). If fluid change doesn't help, torque converter or valve body may need attention—dealer-level diagnosis required. Fluid service is 1 hour; internal repairs are 8-12 hours with trans removal.
Estimated cost: $180-280 (fluid) or $2,500-4,000 (internal)
Buy one if the oil consumption test comes back clean (less than 1 qt per 3,000 mi) and it has CVT service records—otherwise you're gambling on a $4k-6k engine job.
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.