The 2016 718 Cayman with the 2.7L H6 (actually a carryover 981-generation engine, as 718 turbo-four models started mid-2016) is generally reliable, but several catastrophic engine failure modes exist that can total the car economically if not caught early.
Intermediate Shaft (IMS) Bearing Failure (Pre-2009 Carryover Risk)
Rare · high severityTypical onset: 60,000-100,000 mi
Symptoms: Metal shavings in oil during changes, Grinding or whining noise from engine bay at idle, Catastrophic engine seizure with no warning
Fix: If bearing fails, requires complete engine-out teardown, IMS retrofit, and often full rebuild due to metal contamination. 25-35 hours labor for engine removal, bearing replacement, and reinstallation. Preventive replacement (if accessible) is 18-22 hours.
Estimated cost: $8,000-15,000
Cylinder Scoring / Bore Wear Leading to Low Compression
Occasional · high severityTypical onset: 80,000-120,000 mi
Symptoms: Excessive oil consumption (more than 1 qt per 1,000 mi), Blue smoke on cold start, Rough idle and misfires, Loss of power under load
Fix: Compression and leak-down tests confirm. Requires engine removal, cylinder re-boring or sleeve installation, new pistons, rings, and often full short-block replacement if scoring is severe. 30-40 hours labor.
Estimated cost: $12,000-18,000
Transmission Oil Cooler Line Leaks
Common · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Transmission fluid spots under car after parking, Low fluid warnings on dash, Burnt transmission smell, Harsh or delayed shifts if fluid level drops significantly
Fix: Lines age and develop cracks at crimp points or rubber sections. Requires lift access, sometimes undertray removal. Replace all cooler lines and top off fluid. 2-4 hours labor depending on PDK or manual.
Estimated cost: $600-1,200
Engine Mount and Transmission Mount Deterioration
Common · low severityTypical onset: 60,000-90,000 mi
Symptoms: Excessive vibration at idle, Clunking noise during throttle transitions, Shifter feel becomes vague (manual), Visible sagging or cracking of rubber mount
Fix: Mounts are hydraulic-filled and wear from heat cycles. Rear engine mount is most common failure. Engine must be supported from below, 3-5 hours labor for both engine and transmission mounts.
Estimated cost: $1,200-2,000
Coolant Expansion Tank Cracking
Occasional · medium severityTypical onset: 50,000-80,000 mi
Symptoms: Coolant smell in cabin or engine bay, Visible coolant leak on garage floor, Low coolant warning light, Overheating if leak is severe and unnoticed
Fix: Plastic tank develops stress cracks, especially at mounting tabs. Tank is accessible but requires partial undertray removal and coolant drain/refill. 1.5-2.5 hours labor.
Estimated cost: $400-700
PDK Transmission Mechatronic Unit Faults (If Equipped)
Rare · high severitySymptoms: Harsh or delayed shifts, Transmission fault codes and limp mode, Inability to select gears, Juddering during low-speed maneuvers
Fix: Mechatronic unit (valve body with integrated electronics) can fail due to solenoid or sensor issues. Requires transmission drop and mechatronic replacement or rebuild. 12-16 hours labor.
Estimated cost: $5,000-8,500
Rear Main Seal and Intermediate Shaft Seal Leaks
Occasional · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Oil spots under rear of car, Oil visible on bellhousing or flywheel area during inspection, Slight burning oil smell after spirited driving
Fix: Requires transmission or engine removal depending on seal. Rear main seal is 8-12 hours (transmission out). IMS seal often done with clutch jobs. Use OEM seals only.
Estimated cost: $1,800-3,500
Buy one with full service records and oil analysis history; avoid high-mileage examples without proof of proactive maintenance, as engine rebuilds can exceed the car's value.
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.