2002 CHEVROLET CORVETTE C5 Z06

Typical onset: 60,000-100,000 mi

Symptoms: Blue smoke on startup or deceleration, Oil consumption 1 quart per 1,000-2,000 miles, Rough idle when cold, Fouled spark plugs on specific cylinders

Fix: LS6 heads have known valve guide wear issues, especially on exhaust side. Proper fix requires head removal, new guides, seals, and valve job. 12-16 labor hours if you're not pulling the engine, 18-22 if combined with other work. Many shops will quote engine-out for cleaner access.

Estimated cost: $3,500-6,000

Typical onset: 80,000-150,000 mi

Symptoms: Vibration at idle or specific RPM ranges, Belt squeal or misalignment, Rattling noise from front of engine, Check engine light with misfire or crank position sensor codes

Fix: The rubber ring in the harmonic balancer deteriorates and the outer ring separates or wobbles. If caught early, balancer replacement is 2-3 hours. If it's been wobbling and damages the crankshaft keyway, you're looking at crank removal, machining or replacement, and full short block work—25-35 hours labor minimum.

Estimated cost: $300-800 if caught early, $8,000-15,000 if crankshaft damaged

Typical onset: 70,000-120,000 mi

Symptoms: Transmission fluid spots under car near front crossmember, Burnt smell from transmission, Hard or delayed shifts when hot, Transmission fluid dark or burnt on dipstick

Fix: The factory cooler lines rust and leak at crimp fittings, and the small factory cooler is marginal for track use. Replace lines with braided stainless or upgraded hard lines, add auxiliary cooler if driven hard. Lines alone are 2-3 hours, full cooler upgrade 4-6 hours.

Estimated cost: $600-1,800

Typical onset: 60,000-100,000 mi

Symptoms: Clunk when shifting from reverse to drive or vice versa, Vibration in cabin at certain speeds, Shifter rattles or feels loose, Driveline thump on throttle application

Fix: The rubber transmission mount deteriorates and the trans shifts in the tunnel under load. Easy fix from underneath, 1.5-2.5 hours with proper lift access. Upgraded polyurethane mounts last longer but transmit more NVH.

Estimated cost: $300-600

Symptoms: Sudden misfire and loss of power at high RPM, Metallic rattling or ticking noise from valve covers, Check engine light with multiple misfire codes, Compression loss in one or more cylinders

Fix: LS6 valve springs are beehive style and can fail under sustained high RPM (especially 6,000+ RPM), dropping a valve into the cylinder. Results in bent valves, damaged pistons, and sometimes cracked cylinder walls. Requires head removal minimum (12-16 hours), often full rebuild if piston damage occurred (40-60 hours). Common on track cars or aggressive street drivers.

Estimated cost: $4,000-7,000 for head work, $12,000-20,000 for full engine rebuild

Typical onset: 90,000-140,000 mi

Symptoms: ABS light, traction control light, and Active Handling light all on, No ABS function during braking, Speedometer drops to zero intermittently, Service Active Handling message on DIC

Fix: The EBTCM (Electronic Brake Traction Control Module) fails due to internal solder joint cracking. Module is under the driver's seat area. Replacement or repair (some specialists resolder these) takes 1.5-2 hours. Dealer programming required after replacement.

Estimated cost: $800-1,500

Typical onset: 80,000-130,000 mi

Symptoms: Hesitation or stumble under hard acceleration, Loss of top-end power, Hard starting after sitting, Check engine light with lean fuel trim codes

Fix: The in-tank fuel filter sock clogs, and the pump itself can fail. Z06 fuel system is more stressed due to higher flow demands. Tank drop required for pump or filter work, 3-4 hours labor. Preventive replacement every 100k recommended if driven hard.

Estimated cost: $600-1,200