1998 PORSCHE 718 BOXSTER

Typical onset: 60,000-100,000 mi

Symptoms: metallic rattling on cold start, metal shavings in oil, catastrophic engine failure with no warning in worst cases

Fix: Bearing failure grenades the engine. Preventive replacement requires transmission drop, clutch out, and IMS retrofit bearing install—8-12 hours labor. If it fails, you're looking at full engine rebuild or used replacement. Many owners do this proactively with clutch jobs.

Estimated cost: $2,000-3,500 preventive; $8,000-15,000 for engine rebuild after failure

Typical onset: 50,000-90,000 mi

Symptoms: oil drips from bell housing area, oil spots under car after sitting, visible seepage at engine-transmission junction

Fix: The RMS weeps on most 986s eventually. Requires transmission removal—same access as IMS, so smart owners address both simultaneously. Seal itself is cheap, labor is the killer at 8-10 hours.

Estimated cost: $1,800-2,800 standalone; add $300-500 if done with IMS bearing

Typical onset: 80,000-120,000 mi

Symptoms: excessive oil consumption (1 qt per 1,000 mi or worse), blue smoke on startup, loss of compression, rough idle

Fix: Early M96 engines used Lokasil cylinder liners that score vertically, especially if oil changes were stretched. Once scored, you need new cylinder sleeves or a complete engine rebuild. No cheap fix exists—this is major surgery requiring full disassembly.

Estimated cost: $10,000-18,000 for rebuild with LN Engineering sleeves or factory replacement

Typical onset: 70,000-110,000 mi

Symptoms: coolant smell in cabin or engine bay, visible coolant drips under car, low coolant warning light, cracked plastic tank visible on inspection

Fix: Plastic tanks get brittle and crack at mounting tabs or seams. Replacement is straightforward but requires draining system and proper bleeding. 1.5-2.5 hours labor. Always use OEM or high-quality aftermarket—cheap ones fail quickly.

Estimated cost: $300-600

Symptoms: window drops into door, slow or jerky window operation, window won't stay up, clicking noise when operating window

Fix: Plastic regulator components break, most often the drive mechanism. Convertible with failed windows is a security issue. Door panel removal and regulator replacement takes 2-3 hours per side. Aftermarket regulators available but OEM lasts longer.

Estimated cost: $400-700 per window

Typical onset: 80,000+ mi

Symptoms: slow top operation, top won't latch or unlatch, hydraulic fluid stains in trunk, top stops mid-cycle

Fix: Hydraulic lines, cylinders, and pump seals age poorly. Diagnosis takes time to isolate which component failed. Pump replacement is 3-4 hours, cylinders add more. Fluid contamination can damage multiple components, so catching leaks early matters.

Estimated cost: $800-2,500 depending on component