2003 SUBARU BAJA

Typical onset: 90,000-150,000 mi

Symptoms: External oil seepage around head/block mating surface, White exhaust smoke on cold start, Coolant loss with no visible leaks, Overheating under load or in traffic, Milky oil cap residue (if combustion gases enter oil)

Fix: Head gasket replacement requires complete teardown of top end—both heads off, resurface if warped, new gaskets, timing components, water pump while in there. Budget 14-18 labor hours. Many shops recommend six-star or MLS gaskets to prevent repeat failure. If overheated badly, expect machine work or even short block replacement.

Estimated cost: $2,200-3,800

Typical onset: 80,000-140,000 mi

Symptoms: ATF puddles under engine bay, passenger side, Burnt ATF smell, Transmission slipping or delayed engagement if fluid level drops, Pink or red fluid dripping near radiator or frame rail

Fix: Steel lines from transmission to external cooler rust through, especially at fittings and bends. Replace both hard lines and rubber hoses as a set—don't patch one and wait for the next to fail. Add 2-3 hours labor for line replacement, fluid flush, and leak check. Some techs replace cooler itself if corroded.

Estimated cost: $400-800

Typical onset: 70,000-120,000 mi

Symptoms: Clunking on acceleration or deceleration, Vibration at highway speed, Shifter buzz or resonance around 2,000 RPM, Excessive driveline movement visible during hard launches

Fix: Rear diff carrier mount and transmission crossmember mounts crack and sag. Diff mount requires dropping exhaust and rear drivetrain components—about 3-4 hours. Trans mount is quicker at 1.5 hours but often done together. Aftermarket urethane mounts reduce NVH but last longer.

Estimated cost: $350-700

Typical onset: 80,000-130,000 mi

Symptoms: Grinding or humming that increases with speed, Noise changes or worsens in turns, ABS/traction light intermittent or steady, Vibration felt through steering wheel

Fix: Hub assembly replacement, 2-2.5 hours per side including alignment check. AWD system can accelerate wear if one side fails and isn't replaced promptly. Always replace in pairs if one is noisy and the other is original with similar mileage.

Estimated cost: $350-600 per side

Typical onset: 100,000+ mi

Symptoms: Ticking or tapping on cold start that fades when warm, Exhaust smell in cabin, Visible soot around manifold-to-head junction, Failed emissions test due to leak upstream of O2 sensor

Fix: OEM manifolds crack at welds; studs snap off in the head. Aftermarket headers are common upgrades but require O2 sensor bungs and EGT considerations. If studs break, extraction and re-tapping adds 2-4 hours. Gasket and bolt replacement alone is 3-4 hours due to tight quarters on boxer engine.

Estimated cost: $600-1,400

Typical onset: 105,000 mi (service interval)

Symptoms: No symptoms until belt snaps—then engine dies instantly, Coolant seepage from water pump weep hole (advance warning), Squealing or chirping from belt area

Fix: EJ25 is an interference engine—if belt breaks, valves meet pistons and bend. Timing service at 105k mi (or every 7 years) includes belt, tensioner, idlers, water pump, seals. If neglected and belt fails, expect valve job or full head rebuild adding $1,500-3,000 beyond initial service cost. Do it on schedule—8-10 labor hours.

Estimated cost: $800-1,200 (preventive); $3,000-5,000 (if belt breaks)