1998 SUBARU LEGACY GT

Typical onset: 80,000-150,000 mi

Symptoms: Coolant weeping from bottom of engine block, visible at oil pan junction, Sweet smell from engine bay, low coolant reservoir without visible external leaks elsewhere, White crusty residue on engine block below heads, Overheating if left unaddressed

Fix: Both head gaskets must be replaced; single-side failures progress to both. Requires engine removal or extreme contortion in-chassis. Resurface heads, new timing components, water pump while apart. 14-18 hours labor for competent tech doing it in-frame, 20+ for less experienced. Use OEM or Fel-Pro gaskets; multi-layer steel (MLS) aftermarket gaskets require machine work.

Estimated cost: $2,200-3,800

Typical onset: 100,000-180,000 mi

Symptoms: Blue smoke on boost or deceleration, Excessive shaft play in turbo CHRA (check cold, engine off), Loss of boost pressure, sluggish acceleration above 3,000 RPM, Grinding or high-pitched whistle under load

Fix: Turbo oil feed banjo bolt has tiny filter screen that clogs with sludge; starves bearings. Requires new or rebuilt turbo, replacement of all oil feed/return lines, verification of PCV system function. If metal contaminated oil system, full flush necessary. 6-9 hours labor. Inspect for oil consumption issues (rings) before committing to repair.

Estimated cost: $1,800-3,200

Typical onset: 90,000-160,000 mi

Symptoms: Sudden misfire with P0304 code (cylinder 4), Rattling noise from engine on cold start, Loss of compression on cylinder 4 (often <60 PSI when others are 140+), White smoke from exhaust under boost, Pieces of piston land visible in spark plug threads

Fix: The #4 cylinder runs leanest; detonation cracks the ringland between top and second ring. Requires complete short block replacement or full rebuild with forged pistons. Used short blocks available but unknowns on condition. Rebuild while engine is out: 22-28 hours total. Budget for machine work, ARP studs, OEM+ parts.

Estimated cost: $4,500-7,500

Typical onset: 120,000-180,000 mi

Symptoms: Delayed or harsh 2-3 upshift, especially when cold, Slipping on acceleration in 3rd or 4th gear, Burnt ATF smell, dark red or brown fluid, Transmission temp light flashing (duty solenoid C failure), No movement in any gear (catastrophic clutch pack failure)

Fix: The 4EAT behind the turbo EJ25 is borderline inadequate for the torque. Duty solenoid C fails first (4-5 hours, $600-900), but clutch packs wear rapidly if fluid wasn't changed every 30k. Full rebuild or used replacement required for slipping. 12-16 hours R&R plus rebuild. External oil cooler helps longevity but most never got it.

Estimated cost: $2,800-4,200

Symptoms: ATF puddle under car, driver's side near transmission, Low ATF level leading to slipping/overheating, Visible rust perforation on steel hard lines along subframe

Fix: Steel cooler lines rust through where they contact subframe or accumulate road salt. Replace with OEM lines or aftermarket stainless braided if available. 2-3 hours labor, requires lifting car and removing shields. Flush ATF system after repair.

Estimated cost: $350-650

Typical onset: 100,000-200,000 mi

Symptoms: No-start condition, cranks but won't fire, Intermittent stalling when engine is hot, P0335 code (CKP sensor circuit), Tachometer drops to zero while driving before stall

Fix: Sensor mounts behind timing cover on driver's side of block; heat-soak kills it. Requires removal of accessory belts, crank pulley, timing covers. 3-4 hours labor. Use OEM sensor; aftermarket failures common. Test connector and wiring for corrosion before condemning sensor.

Estimated cost: $450-750

Typical onset: 130,000-200,000 mi

Symptoms: Whining or humming from rear that increases with speed, Noise changes pitch in turns (louder on one side), Clunking from rear on deceleration if severe

Fix: Rear diff carrier bearings wear from lack of fluid changes (30k interval ignored). Requires diff removal, teardown, bearing replacement, and setup with shims/preload. 6-8 hours labor. Confirm it's not wheel bearings first (jack and spin wheels). Fluid changes every 30k prevent this.

Estimated cost: $900-1,500