The 2006 Cayman S is essentially a first-gen 987 platform with the 3.4L M97 flat-six, sharing the infamous intermediate shaft bearing (IMS) and bore-scoring issues that plague mid-2000s Porsche engines. When these motors let go, they let go hard—but survivors past 100k with proper maintenance can be solid drivers.
IMS Bearing Failure (Intermediate Shaft)
Occasional · high severityTypical onset: 40,000-80,000 mi
Symptoms: Metal shavings in oil filter or drain oil, Rough cold starts or unusual rattling from engine, Catastrophic engine failure without warning in worst cases
Fix: Preventive IMS bearing replacement requires dropping the transmission and clutch, 12-16 hours labor. If it fails, you're looking at full engine rebuild or replacement. Many owners do this preemptively with clutch jobs.
Estimated cost: $2,500-4,000 preventive retrofit; $15,000-25,000 if engine damage occurs
Bore Scoring / Cylinder Wall Damage
Occasional · high severityTypical onset: 60,000-100,000 mi
Symptoms: Excessive oil consumption (more than 1 qt per 1,000 mi), Blue smoke on cold start or deceleration, Loss of compression in one or more cylinders, Rough idle and misfires as wear progresses
Fix: Borescope inspection confirms scoring. Fix requires complete engine teardown, cylinder replating or Nikasil resleeve, new pistons/rings. 40-60 hours labor for full rebuild. Some opt for used/rebuilt long blocks.
Estimated cost: $12,000-20,000 depending on machine work scope
Rear Main Seal (RMS) Oil Leak
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Oil drips or puddles under center of car after sitting, Oil visible on bellhousing or transmission case, Clutch contamination in severe cases
Fix: Requires transmission and clutch removal to access seal. Smart to replace IMS bearing simultaneously. 10-14 hours labor just for RMS, but always bundled with clutch or IMS work.
Estimated cost: $1,800-3,000 standalone; $500-800 if combined with clutch/IMS job
Coolant Expansion Tank Cracking
Common · medium severityTypical onset: 70,000-120,000 mi
Symptoms: Coolant smell in cabin or engine bay, Visible coolant seepage at tank seams, Low coolant warning light intermittent or constant, Overheating if leak progresses unchecked
Fix: Plastic tank becomes brittle with age and heat cycling. Replacement is straightforward, 1-2 hours including bleeding system. Upgraded aluminum tanks available aftermarket.
Estimated cost: $300-600
Transmission Mount Failure
Common · low severityTypical onset: 60,000-100,000 mi
Symptoms: Clunking on shifts or throttle transitions, Vibration through chassis at idle in gear, Excessive driveline movement visible under load
Fix: Rubber mounts deteriorate from heat and age. Front and rear mounts both wear. 2-3 hours labor total, accessible from below. Replace both sides at once.
Estimated cost: $600-1,000
Fuel Filter Clogging
Occasional · low severityTypical onset: 80,000-120,000 mi
Symptoms: Hesitation or stumble under hard acceleration, Rough running or surging at highway speeds, Difficulty starting after sitting overnight
Fix: In-tank fuel filter assembly not commonly serviced; Porsche considers it 'lifetime.' Filter can clog with age or contaminated fuel. Requires dropping fuel tank, 3-4 hours labor.
Estimated cost: $500-900
Air-Oil Separator (AOS) Failure
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Excessive oil consumption without visible leaks, Smoke from exhaust on deceleration, Oil sucked into intake manifold causing rough idle, Check engine light for lean/rich codes
Fix: Diaphragm inside AOS fails, allowing crankcase pressure to push oil into intake. Located on right side of engine, 3-4 hours labor, requires removing airbox and some cooling lines.
Estimated cost: $800-1,400
Buy one only if IMS bearing is documented as replaced or you budget $3k immediately for the retrofit; survivors are fantastic drivers, but the engine grenades are financially catastrophic.
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.