1999 PORSCHE 718 BOXSTER

Typical onset: 40,000-80,000 mi

Symptoms: Metallic debris in oil during changes, Rough idle or misfires developing suddenly, Catastrophic engine failure with no warning—bearing disintegrates, destroys engine internally, Some cases show zero symptoms until complete failure

Fix: Preventive replacement requires transmission drop, clutch out, and IMS retrofit bearing installation—8-12 hours labor. After failure, you're looking at complete engine rebuild or replacement with known-good used motor. Many owners do this preemptively around 60k mi.

Estimated cost: $2,000-3,500 preventive replacement; $12,000-18,000 post-failure engine rebuild

Typical onset: 60,000-120,000 mi

Symptoms: Blue smoke on cold start that clears after warm-up, Increasing oil consumption—quart every 500-1000 miles, Loss of compression in one or more cylinders, Rough running, misfires on affected cylinders

Fix: The Lokasil cylinder coating wears through, requiring either sleeved cylinder installation or complete engine replacement. This is a full teardown—40-60 hours for proper rebuild with new Nikasil-coated cylinders or aftermarket sleeves. No half-measures work here.

Estimated cost: $8,000-15,000 for cylinder sleeving/rebuild; $6,000-10,000 for used replacement engine plus install

Typical onset: 50,000-90,000 mi

Symptoms: Oil pooling under car after sitting overnight, Oil spots on transmission bell housing, Gradual oil level drop requiring frequent top-offs, Visible oil weepage at engine/transmission junction

Fix: Requires transmission removal to access the seal—same labor as IMS bearing job. Smart owners combine RMS replacement with IMS bearing service and clutch replacement if near these mileages. 8-10 hours labor standalone.

Estimated cost: $1,500-2,500 standalone; $500-800 added cost if done during IMS/clutch service

Typical onset: 80,000-120,000 mi

Symptoms: Coolant smell in engine bay, Visible coolant leaks on left side of engine compartment, Low coolant warning light with no external puddles, Plastic tank develops stress cracks at mounting points

Fix: Plastic tank becomes brittle with age and cracks at the seams or mounting tabs. Replacement is straightforward—drain system, unbolt old tank, install new upgraded unit. 1.5-2 hours labor. Use OEM or upgraded aluminum aftermarket tank.

Estimated cost: $300-600

Typical onset: Any—age-related, not mileage

Symptoms: Top operates slowly or stops mid-cycle, Hydraulic fluid leaking from cylinders or lines, Top won't latch properly—manual assist needed, Pump runs but top doesn't move

Fix: Hydraulic cylinders, lines, and pump seals deteriorate over 20+ years. Individual cylinder replacement is 2-4 hours depending on which one fails. Complete system overhaul with all new cylinders, lines, and pump rebuild is 6-8 hours. Many owners live with manual operation.

Estimated cost: $800-1,500 single cylinder; $2,500-4,000 complete system overhaul

Typical onset: Any—mechanical wear item

Symptoms: Window drops into door and won't rise, Clicking or grinding noise when operating window, Window goes up crooked or binds, Window falls down while driving

Fix: Plastic regulator mechanism wears and breaks—very common Boxster issue. Door panel removal, regulator swap. 2-3 hours per side. Aftermarket improved-design regulators available and recommended over OEM.

Estimated cost: $400-700 per door