Porsche Boxster S 3.2 987

The M96.26 engine uses an intermediate shaft (IMS) bearing that connects the two banks of timing chains. Early 2005 model year Boxster S cars received the older small single-row bearing with a failure rate estimated at 5-8%. Late 2005 and all 2006 models received an improved larger single-row bearing with failure rates under 1%. When the bearing fails, metal debris contaminates the engine oil and causes catastrophic internal damage. Preventive replacement with an upgraded aftermarket bearing (LN Engineering, EPS) costs approximately €1,500-2,500 including labor (9-12 hours). If the bearing has already failed and damaged the engine, a full rebuild runs €8,000-15,000. The IMS bearing can be replaced at the same time as a clutch job (which requires gearbox removal anyway), saving significant labor costs. Always verify the build date: cars built after approximately mid-2005 have the improved bearing.

The air-oil separator is a wear item on M96 engines that typically fails between 80,000 and 120,000 km. When the internal diaphragm breaks down, oil vapor is pulled into the intake manifold and burned, causing white or blue exhaust smoke on startup and increased oil consumption. A secondary effect is that oil can seep past the rear main seal due to increased crankcase pressure. On the 987, the AOS is accessible from the top of the engine, making replacement relatively straightforward (2-3 hours labor). OEM replacement costs around €150-200 for the part. Many specialists recommend upgrading to the Porsche Motorsport or LN Engineering unit (€250-350) for improved longevity. Total repair including labor is typically €400-800.

The rear main seal sits between the engine and the gearbox and deteriorates over time. Oil seepage typically becomes visible after 80,000-120,000 km. The seal itself is inexpensive (€50-80), but replacement requires removing the entire gearbox (10-12 hours labor), which makes it one of the more expensive repairs on the Boxster. Most specialists recommend combining RMS replacement with clutch and IMS bearing work if any of those jobs are due, since they all require gearbox removal. A minor seep can be monitored; active dripping should be addressed promptly. Total cost at a specialist is typically €1,200-2,500 depending on what additional work is combined.

The water pump on the M96 engine is a known weak point, typically failing between 60,000 and 100,000 km. The plastic impeller vanes can break off and circulate through the cooling system, and the pump bearings can seize. Symptoms include a knocking noise from behind the driver's seat, coolant temperature rising, or visible coolant leaks. The pump sits at the rear of the engine and requires moderate disassembly to access. Parts cost approximately €200-350 for the pump and thermostat. Many specialists recommend replacing both the water pump and thermostat together as a preventive measure. Total repair cost at a specialist is typically €800-1,500 including labor.

The 987 uses plastic coolant pipes and an expansion tank that degrade over time. The expansion tank is particularly prone to developing hairline cracks at the seams, causing slow coolant loss and a faint coolant smell while driving. The plastic water guide housing between the engine and cabin bulkhead can also crack at its mold seam. Early 987 models (2005-2006) used an older tank design that is more susceptible. Replacement parts cost €100-250 each, but labor varies depending on which component has failed. If a coolant pipe fails suddenly while driving, the resulting overheating can cause serious engine damage. Always check coolant level regularly and address any drop promptly.

The cable-driven window regulators are a common failure point on 987 Boxsters. The thin steel cables that raise and lower the heavy frameless glass stretch and eventually snap, producing a distinctive grinding or crunching noise when the window switch is pressed. Failure is more common in colder climates where ice can cause the glass to bind, putting extra strain on the mechanism. The regulator assembly costs approximately €150-250, and replacement takes 2-3 hours labor. Since the Boxster is a convertible with frameless windows, proper window operation is essential for sealing. Both sides typically fail within a few years of each other.

Porsche issued a Technical Service Bulletin for cracked ignition coil housings on 987 models. Heat cycling causes the plastic housings to develop cracks, allowing moisture to enter and corrode the internal components. Symptoms include rough idle, misfires (especially when warm), and check engine lights. Each coil costs €50-80, and there are six on the flat-six engine. Many owners replace all six coils preventively when one fails, since the others are typically similarly aged. Including spark plugs and labor, a complete set replacement runs approximately €400-600.

The power-operated convertible top uses a hydraulic system with plastic transmission gears that can split and lose teeth after many cycles. Symptoms include the top stopping mid-cycle, a clanking noise during operation, or the top not latching securely. The gearbox component costs approximately €500-700 for the part. Hydraulic cylinder leaks are another potential failure, though less common. The side beading (weather seal strip along the top of the doors) can also separate with age, causing wind noise and water leaks. Beading replacement is relatively inexpensive (€100-200 per side) but should be addressed to prevent interior water damage.