2002 SUBARU WRX STI

Typical onset: 60,000-120,000 mi

Symptoms: Misfires on cylinder 4 under boost, Loss of compression on #4, Excessive blow-by or oil consumption, Metallic knock or rattle under load

Fix: Pull engine, split cases, replace all pistons and rings. Smart shops do all four pistons even if only #4 cracked. Expect 20-30 hours labor plus machine work if cylinder wall scoring occurred. Many owners opt for forged piston upgrade at this point.

Estimated cost: $4,500-8,000

Typical onset: 80,000-140,000 mi

Symptoms: Oil seepage at block/head mating surface, driver's side more common, Burning oil smell after hard driving, Visible oil crust around head bolt area, Not typically coolant mixing (that's NA EJ issue)

Fix: Engine-out job for proper access. Replace both head gaskets, ARP studs recommended, resurface heads if warped. 16-22 hours labor. Do timing belt, water pump, and all seals while you're in there or you're doing it twice.

Estimated cost: $2,800-4,200

Typical onset: 70,000-110,000 mi

Symptoms: Grinding or crunching into 2nd gear, especially when cold, Gear pop-out under deceleration in 2nd, Difficulty engaging 2nd at higher RPM shifts

Fix: Trans out, split case, replace 2nd gear synchro assembly. Most shops replace all synchros and inspect forks at this point since you're already 12-15 hours deep. OEM synchros only — aftermarket ones are junk.

Estimated cost: $2,200-3,500

Symptoms: Turbo whine or whistle under boost, Blue smoke on deceleration, Low oil pressure at idle after spirited driving, Catastrophic turbo failure if ignored

Fix: The banjo bolt filter screens clog with carbon and sludge, starving the turbo of oil. Remove turbo oil feed line, clean or replace banjo bolts and screens. 2-3 hours labor. If turbo is already damaged, add another $1,200-2,000 for CHRA or replacement.

Estimated cost: $300-600

Typical onset: 90,000-150,000 mi

Symptoms: Rod knock: metallic tapping that increases with RPM, Low oil pressure warning light, Metal flakes in oil filter during changes, Sudden catastrophic failure if driven after knock starts

Fix: Engine out, full teardown, inspect crank journals for scoring. If crank is damaged, needs grinding or replacement. Replace all rod and main bearings minimum. 25-35 hours labor. Most opt for short block replacement at this point since you're already there.

Estimated cost: $5,000-9,000

Typical onset: 60,000-100,000 mi

Symptoms: Excessive drivetrain clunk on acceleration or deceleration, Vibration in cabin at idle in gear, Shifter feels sloppy or moves excessively

Fix: Replace transmission crossmember mount and pitch stop mount. The OEM rubber deteriorates quickly under aggressive driving. 1.5-2.5 hours labor. Upgrade to polyurethane mounts adds NVH but tightens drivetrain response.

Estimated cost: $250-450

Typical onset: 80,000-120,000 mi

Symptoms: Transmission fluid spots under car near radiator area, Low fluid level in transmission, Transmission overheating on highway runs or track days

Fix: Replace transmission oil cooler lines and fittings. Lines corrode from road salt and deteriorate from heat cycles. 2-3 hours labor. Some shops replace the cooler itself if it's leaking internally into coolant (rare but catastrophic).

Estimated cost: $350-700