The 2018 Impreza rides on Subaru's Global Platform with the FB20 2.0L flat-four and CVT. While this generation improved refinement over previous models, it introduced CVT cooling issues and unfortunately carried forward oil consumption problems that can lead to catastrophic engine damage if ignored.
Excessive Oil Consumption Leading to Engine Failure
Common · high severityTypical onset: 40,000-80,000 mi
Symptoms: Low oil warning light between changes, potentially burning 1qt per 1,000-2,000 miles, Blue smoke from exhaust on cold start or acceleration, Check engine light with lean codes (P0171/P0174) from oxygen sensor oil fouling, Eventual rod knock or complete seizure if oil starvation occurs
Fix: Root cause is piston ring design and bore glazing. Subaru extended warranty covered some cases, but many owners are post-warranty. Requires complete short block replacement (8-12 labor hours) or full engine rebuild with updated pistons and rings (15-20 hours). Many opt for factory short block with 3yr/36k warranty. DIY ring replacement rarely solves it permanently.
Estimated cost: $5,500-8,500
CVT Transmission Oil Cooler Line Leaks
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Red transmission fluid pooling under vehicle, typically passenger side, Burnt smell after highway driving, CVT overheat warning on dash in extreme cases, Fluid level drops requiring frequent top-ups
Fix: The external cooler lines and their crimp connections fail, sometimes at the cooler itself. Requires line replacement and often the cooler assembly (2-3 labor hours). Must use genuine Subaru CVT fluid (High Torque). Some techs see repeat failures if aftermarket lines are used.
Estimated cost: $600-1,200
PCV Valve System Causing Rough Idle and Stalling
Occasional · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Rough idle that worsens when warm, Intermittent stalling at stops or low RPM, Check engine light with P0507 (idle control) or P0171/P0174 (lean codes), Oil residue in intake manifold and throttle body
Fix: The PCV valve integrated into the valve cover clogs with sludge, especially with extended oil change intervals. This was subject to recall for 2017-2019 models. Requires valve cover replacement (not serviceable separately) at 2-3 labor hours, plus intake cleaning. Extended oil changes accelerate this dramatically.
Estimated cost: $800-1,400
Transmission Mount Failure
Occasional · low severityTypical onset: 70,000-120,000 mi
Symptoms: Clunking when shifting from Park to Drive or Reverse, Excessive vibration at idle in gear, Visible engine/trans movement when revving in Park, Accelerated wear on other mounts and CVT components
Fix: The rear transmission mount deteriorates, allowing excessive powertrain movement. Common on all Subarus but this platform sees it earlier. Replacement is straightforward (1.5-2 hours) but requires supporting the transmission. Recommend replacing all three engine mounts if one fails around 100k miles.
Estimated cost: $300-600
Headlight Condensation and LED Failure
Occasional · low severitySymptoms: Moisture visible inside headlight housing, LED daytime running light or low beam flickering or going dark, Uneven light output or shadowing, Check engine light with U0073 (control module communication) in severe cases
Fix: Poor headlight sealing allows moisture intrusion which corrodes LED driver circuitry. Some units were recalled but problem persists. Requires complete headlight assembly replacement (aftermarket rarely fits properly). 1 hour labor per side but parts are expensive ($400-700 each OEM).
Estimated cost: $500-900
Fuel Pump Failure
Rare · high severityTypical onset: 60,000-100,000 mi
Symptoms: No-start condition with full tank of gas, Intermittent stalling under load or during acceleration, Whining noise from rear seat area, Check engine light with P0087 (fuel rail pressure too low)
Fix: Low-pressure fuel pump (in-tank) fails prematurely on some units, potentially related to recalled impeller defect. Requires fuel tank drop and pump assembly replacement (3-4 hours). Subaru issued recall 19V-666 for certain build dates. Check VIN eligibility before paying out of pocket.
Estimated cost: $800-1,400
A comfortable reliable daily driver if you win the engine lottery, but the oil consumption gamble makes this a risky used buy without comprehensive engine warranty — budget $6k-8k for potential short block replacement.
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.