The 2021 718 Cayman represents the final year of the 982 generation, with the base 2.0L turbo four being generally reliable but the 2.7L turbo flat-six (GTS models) facing catastrophic bore scoring issues that can destroy engines. These are otherwise solid mid-engine sports cars with typical Porsche PDK reliability, but the engine lottery on six-cylinder variants is a serious financial risk.
Cylinder Bore Scoring / Piston Ring Failure (2.7L Turbo H6)
Occasional · high severityTypical onset: 30,000-60,000 mi
Symptoms: excessive oil consumption (1 qt per 1000 mi or worse), cold-start smoke from exhaust, rough idle when warm, loss of compression, metallic rattling from engine bay
Fix: Complete engine rebuild or short block replacement required. Includes pistons, rings, bore honing or re-sleeving, bearings, gaskets. 40-60 hours labor depending on approach. Some owners go full rebuild with IMS-style upgrades while apart. This is a known defect on the 2.7L DFI turbo engines—affected batches have inadequate piston-to-bore clearance causing micro-seizures and scoring.
Estimated cost: $18,000-28,000
Transmission Oil Cooler Line Leaks
Occasional · medium severityTypical onset: 40,000-70,000 mi
Symptoms: transmission fluid spots under car, low PDK fluid warning on dash, harsh shifts when cold, burnt smell from undercarriage
Fix: Replace transmission oil cooler and associated hard lines. Access requires removal of rear undertray and sometimes exhaust components. Lines corrode at crimps or develop stress cracks. 3-5 hours labor plus fluid refill and adaptation procedure.
Estimated cost: $1,200-2,000
Transmission Mount Failure
Common · medium severityTypical onset: 50,000-80,000 mi
Symptoms: clunking when shifting or launching, excessive drivetrain movement, vibration at idle in gear, visible tearing of rubber isolators
Fix: Replace transmission mount (large dogbone mount connecting trans to subframe). Access from underneath, trans does not need to drop but exhaust and heat shields must come off. 2-3 hours labor. This is a wear item on hard-driven cars—track use accelerates failure significantly.
Estimated cost: $600-1,000
Fuel Filter Clogging (Ethanol Fuel)
Occasional · medium severitySymptoms: intermittent stumbling or hesitation under load, lean fuel trim codes, rough running after refueling, limp mode during spirited driving
Fix: Replace in-tank fuel filter assembly. Requires fuel tank drop or significant disassembly depending on approach. Issue more common with E10 fuel in regions with inconsistent fuel quality—particulates accumulate faster than Porsche anticipated. 4-6 hours labor including tank removal.
Estimated cost: $800-1,400
PDK Mechatronic Sleeve Seals (7-Speed)
Rare · high severityTypical onset: 60,000-100,000 mi
Symptoms: delayed engagement into gear, harsh downshifts, transmission fault codes, slipping between gears, metallic debris in fluid at service
Fix: Mechatronic unit seal failure allows contamination of hydraulic control unit. Requires transmission removal, mechatronic disassembly, sleeve replacement, and full fluid flush. 12-16 hours labor. If caught early, just seals; if driven with contaminated fluid, entire mechatronic or clutch packs may need replacement.
Estimated cost: $4,000-8,000
Coolant Expansion Tank Cracking
Occasional · medium severityTypical onset: 40,000-90,000 mi
Symptoms: coolant smell in cabin or engine bay, coolant level dropping, visible cracks on tank body near mounting points, overheating warning
Fix: Replace expansion tank and pressure cap. Plastic becomes brittle with heat cycling. Located in front trunk area with reasonable access. 1-2 hours labor plus coolant flush and bleed. Preventive replacement recommended if visible stress cracks present.
Estimated cost: $400-700
Buy the base 2.0L turbo with confidence; approach any 2.7L GTS or S model with PPI including leak-down test and oil analysis—budget $20k for potential engine replacement.
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.