The 2002 Park Avenue is a comfortable full-size sedan built on GM's G-body platform with the venerable 3800 Series II V6. While the naturally-aspirated version is generally bulletproof, the Ultra trim's supercharged variant brings significant head gasket and cooling issues, and all models share 4T65-E transmission vulnerabilities.
Lower Intake Manifold Gasket Failure (3800 Series II)
Common · medium severityTypical onset: 80,000-140,000 mi
Symptoms: Coolant loss with no visible external leaks, White residue or 'milkshake' in oil if severely neglected, Rough idle or misfire when cold, Sweet coolant smell from exhaust
Fix: Replace lower intake manifold gaskets with updated Felpro or Dorman metal-carrier design; includes coolant flush and often spark plugs while you're in there. 4-6 hours labor.
Estimated cost: $600-1,100
Supercharger Head Gasket Failure (3.8L SC Ultra only)
Occasional · high severityTypical onset: 100,000-150,000 mi
Symptoms: Persistent coolant loss even after intake gaskets done, White smoke from exhaust on startup, Overheating under load or in traffic, Bubbles in coolant reservoir when running
Fix: Head gasket job on the supercharged 3800 requires removing the supercharger, intercooler, and accessories. Often find warped heads needing machining. Studs recommended over bolts. 12-16 hours labor, can spiral if heads crack.
Estimated cost: $2,500-4,500
4T65-E Transmission Pressure Control Solenoid and Cooler Line Failure
Common · high severityTypical onset: 90,000-130,000 mi
Symptoms: Harsh or delayed 1-2 shift, especially when cold, Check Engine light with P1811 code (maximum adapt long shift), Transmission fluid weeping from radiator cooler connections, Slipping under moderate throttle
Fix: Pressure control solenoid (PCS) replacement requires pan drop, filter, fluid. Cooler lines rust through at crimps and need replacement before they leak into radiator. Full flush recommended. 3-5 hours for solenoid; add 2 hours if doing lines.
Estimated cost: $800-1,400
Front Lower Control Arm Bushings and Ball Joints
Common · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Clunking over bumps, especially from front corners, Steering wander or vague on-center feel, Uneven or cupped inner tire wear, Steering wheel vibration on rough roads
Fix: Lower control arms typically replaced as assemblies since bushings aren't serviceable separately on most aftermarket parts. Ball joints can fail independently. Alignment mandatory after. 3-4 hours labor for both sides.
Estimated cost: $600-1,000
Electronic Throttle Body Carbon Buildup (Drive-by-Wire)
Occasional · low severityTypical onset: 60,000-120,000 mi
Symptoms: Rough or hunting idle, especially when warm, Hesitation or stumble on light throttle, Check Engine light with P0506 (idle too low) or P0507 (too high), Stalling when coming to a stop
Fix: Remove throttle body and clean butterfly valve and bore with throttle body cleaner. Requires idle relearn procedure after reinstall. 1.5-2 hours labor if you're careful not to damage the coating.
Estimated cost: $150-300
Power Steering Pressure Hose and Rack Seepage
Common · low severityTypical onset: 80,000-140,000 mi
Symptoms: Power steering fluid spots on driveway under engine bay, Groaning or whining when turning at low speeds, Hissing sound at idle with wheels turned, Fluid level drops every few weeks
Fix: High-pressure hose from pump to rack develops seepage at crimps; rack inner seals leak onto bellows. Hose is 1.5 hours; rack replacement (if seeping badly) is 4-5 hours and requires alignment.
Estimated cost: $250-450 (hose); $800-1,400 (rack)
Buy the naturally-aspirated version under 100k miles with service records and you'll have a comfortable, reliable cruiser; avoid the Ultra unless head gaskets are documented as recently done.
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.