Porsche Boxster 987

The 987.1 (2005-2008) uses the Gen III IMS bearing, which has an estimated failure rate of approximately 1% - a massive improvement over the 986's single-row bearing (8-10%). Early 2005 production cars may have the older Gen II bearing with higher failure rates, so verify your build date. The 987.2 (2009-2012) eliminated the IMS bearing entirely, making this a non-issue. When the bearing does fail, metal debris circulates through the engine and causes catastrophic internal damage. Preventive IMS bearing upgrade costs €1,500-2,500 including labor (8-10 hours, gearbox must be removed). If the bearing fails before replacement, expect €8,000-12,000 for engine rebuild. Specialists recommend combining IMS upgrade with RMS and clutch replacement since the gearbox is already removed. Always verify IMS bearing status on any 987.1 before purchase.

The M96/M97 engine's open-deck crankcase design allows cylinders to distort under thermal stress. Cylinder 6 runs hottest and is most susceptible. However, the 2.7L base engine is considerably less prone to bore scoring than the 3.2L/3.4L S variants for two reasons: the smaller displacement puts less thermal stress on the cylinders, and the port-injection system (unlike the S model's DFI on 987.2) does not wash lubricant from cylinder walls. Forum evidence suggests bore scoring on 2.7L engines is rare but not impossible. A bore scope inspection before purchase costs €100-200 and is essential for any 987.1. If scoring is found, repair requires Nickies cylinder sleeves with forged pistons, costing €5,000-6,000 for cylinder work alone, plus €4,000-6,000 for engine removal and rebuild. The 987.2 uses an improved Alusil crankcase with better oiling (4 scavenge pumps vs 2) and is far less susceptible.

The rear main seal sits where the crankshaft exits the engine to meet the gearbox. Porsche redesigned this seal multiple times across the 987 production run but the issue persists, particularly on higher-mileage cars. When the seal fails, oil leaks onto the flywheel, clutch disc, and bellhousing. In severe cases, the contaminated clutch requires replacement as well. The seal itself costs under €50, but the gearbox must be removed for access, making it a labor-intensive repair (8-10 hours). Standalone RMS replacement costs €1,200-1,800 at a specialist. Most specialists recommend combining RMS replacement with clutch renewal and IMS bearing upgrade (on 987.1) since the gearbox is already removed, bringing total cost to €2,500-4,000 for the combined job.

The AOS is a crankcase ventilation device that separates oil from blow-by gases. The internal diaphragm deteriorates with age and heat exposure, typically failing between 60,000-100,000 km. Symptoms include rough or hunting idle, increased oil consumption, blue or white exhaust smoke, and various fault codes. The genuine Porsche replacement part costs €80-150. Labor is 3-4 hours on the Boxster (harder to access than the Cayman). Total replacement cost at a specialist is €400-900. If left uncorrected, a failed AOS can contribute to bore scoring by leaning out the fuel mixture. Porsche specialists recommend treating the AOS as a maintenance item and replacing it every 6 years or 100,000 km. Always use genuine Porsche parts as aftermarket units have poor longevity.

Two related cooling system weak points affect the 987. The water pump uses a plastic impeller that can shed blades over time, reducing coolant flow and causing localized overheating. Broken impeller fragments can block passages in the cylinder heads. The plastic coolant expansion tank becomes brittle after 8-10 years and develops hairline cracks that may only leak under pressure. Both issues create overheating risk that can accelerate bore scoring. Water pump replacement costs €400-700 (upgraded metal impeller pumps are available from aftermarket suppliers). Expansion tank replacement costs €300-500 including coolant refill and bleed. Both should be considered preventive maintenance on any 987 still running original components. Watch for slow coolant level drops or faint coolant smell while driving.

The Boxster's electrically operated convertible top uses a complex mechanism with transmission gears, push rods, cables, and motors. The most common failure is cracked transmission gears, which cause a clunking noise during operation and eventually prevent the roof from opening or closing. Individual gear replacement is possible for €80-100 in parts (3-4 hours labor), making this a relatively affordable fix if caught early. Push rod replacements are similarly inexpensive. However, if the motor or complete transmission assembly needs replacement, costs rise to €1,500-2,500. The convertible top fabric itself lasts approximately 10-15 years before showing wear, with replacement costing €1,500-2,500 including labor. Regular use and proper lubrication of guide rails extends mechanism life.

The 987 Boxster's front-mounted radiators and AC condensers sit behind open vents with no protective screens from the factory. Leaves, road debris, and insects accumulate between the radiator and condenser, trapping moisture that causes progressive corrosion. Once corrosion starts, the aluminum cores develop pinhole leaks that cannot be reliably repaired. Radiator replacement costs €400-800 per unit (there are two), and AC condenser replacement costs €300-600. Total cost for replacing both radiators and the condenser reaches €1,200-2,000. Prevention is straightforward: clean out debris from behind the front bumper cover every spring and consider installing aftermarket mesh screens. Reduced cooling efficiency manifests as slightly higher running temperatures, especially in traffic.