The 2021 Legacy XT uses Subaru's FA24 2.4L turbo boxer paired with a CVT. While newer than previous-gen EJ engines, early FA24s show concerning patterns of oil dilution, transmission cooler failures, and catastrophic engine failures—sometimes under warranty mileage.
FA24 Turbo Engine Oil Dilution & Bearing Failure
Occasional · high severityTypical onset: 30,000-70,000 mi
Symptoms: Rising oil level on dipstick between changes, Fuel smell in oil, Rod knock or bearing noise at cold start, Sudden catastrophic failure with metal shavings in oil
Fix: TSB covers inspection but not always root cause. Severe cases need short block or full rebuild—12-18 labor hours depending on machine shop work. Some dealers replace under extended warranty; independents see grenaded engines needing bearings, pistons, rods.
Estimated cost: $6,000-12,000
CVT Transmission Oil Cooler Line Failure
Common · high severityTypical onset: 40,000-80,000 mi
Symptoms: Red ATF puddle under engine bay passenger side, Sudden loss of transmission fluid, CVT overheating warning light, Transmission slipping or unable to move vehicle
Fix: Cooler line corrodes or cracks at crimp point. Replace line and cooler assembly, flush CVT, refill—4-6 hours labor. If caught early, CVT survives; if run low, expect internal CVT damage adding $4k-8k.
Estimated cost: $800-1,500
Transmission Mount Failure (Rear/Pitch Stop)
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Clunk or thud on acceleration or deceleration, Excessive engine/trans movement visible from engine bay, Vibration felt through shifter area at idle
Fix: Rear transmission mount (pitch stop) degrades faster on turbo models. Replace mount—1.5-2 hours. Often comes with upgraded aftermarket bushings to prevent repeat.
Estimated cost: $300-600
Head Gasket Seepage (Early Production)
Occasional · medium severityTypical onset: 50,000-100,000 mi
Symptoms: Oil residue on cylinder head exterior, Slight coolant smell or minor oil consumption, No overheating but visible weeping at head/block interface
Fix: Not the catastrophic EJ failure, but FA24 can seep oil externally from head gasket. Requires head gasket replacement both sides—8-12 hours including machine shop resurface if needed.
Estimated cost: $2,500-4,000
Fuel System Contamination / Clogged Fuel Filter
Rare · medium severitySymptoms: Rough idle, misfires, reduced power, Check engine light for fuel trim/misfire codes, Surging or hesitation under load
Fix: In-tank fuel filter not serviceable separately; requires fuel pump assembly replacement. Bad gas or tank contamination accelerates this. 3-4 hours labor for pump R&R.
Estimated cost: $600-1,200
Turbocharger Wastegate Rattle
Occasional · low severityTypical onset: 60,000-100,000 mi
Symptoms: Metallic rattle at idle or light throttle when warm, Rattle disappears under boost, No performance loss initially
Fix: Wastegate actuator arm develops play. Turbo replacement recommended long-term but can run months without failure. Turbo R&R 6-8 hours; some try actuator replacement alone (shade-tree fix).
Estimated cost: $1,800-3,000
Avoid early 2021s if possible; late-2021+ builds seem better but FA24 reliability is unproven long-term—too many catastrophic failures for a 3-year-old car.
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.