BMW M2 Competition F87

The S55 uses a multi-piece friction-fit crank hub that can slip on the crankshaft, misaligning the timing chain and causing piston-to-valve contact. Specialists estimate this affects 2-3% of S55 engines, with the risk escalating on tuned or track-driven cars. On stock cars driven normally, the failure rate appears to be under 1%. When it does happen, it is catastrophic: a slipped hub can destroy the engine internals. Preventive solutions include a capture plate (approximately 1,500-2,000 euros installed, 4-5 hours labor) or a one-piece pinned crank hub upgrade (approximately 2,000-2,500 euros at a UK/European specialist). If the hub has already slipped and caused damage, engine rebuild costs can reach 8,000-15,000 euros depending on the extent of internal damage. Many specialists recommend the preventive fix for any car that will see track use or tuning beyond stock.

The S55 valve cover gasket is one of the most common failure points, typically beginning to leak between 60,000 and 100,000 km. The rubber hardens and cracks from constant heat cycling. Oil seeps down the engine block and can reach the exhaust manifold, creating a burning smell and fire risk if neglected. The gasket is integrated into the valve cover on later S55 revisions, sometimes requiring full cover replacement. At an independent specialist, expect 800-1,000 euros. BMW dealers charge 1,200-1,400 euros. Many owners combine this with spark plug and ignition coil replacement to save on overlapping labor.

Like all direct injection engines, the S55 does not spray fuel over the intake valves, so oil vapors from the crankcase ventilation system bake carbon deposits onto the valve stems and ports. This gradually restricts airflow and reduces performance. Symptoms include rough idle, hesitation on light throttle, and gradual power loss, typically becoming noticeable between 60,000 and 90,000 km. Walnut shell blasting is the standard cleaning method. Independent specialists charge 600-800 euros, while BMW dealers quote 1,000-1,200 euros. Expect to need this every 50,000-70,000 km depending on driving style. Regular high-RPM driving and quality fuel with detergent additives help slow the buildup but cannot prevent it entirely.

The S55 has two distinct boost plumbing concerns. The plastic charge pipe can crack or blow off under boost, causing sudden power loss and limp mode. This is a straightforward fix: an aftermarket aluminum charge pipe costs 150-250 euros and eliminates the problem permanently, with total repair cost around 200-400 euros installed. More seriously, the air-to-water intercooler (charge cooler) has plastic end tanks that can develop internal coolant leaks. If coolant enters the intake and reaches the cylinders, it can cause catastrophic engine damage. There are documented cases of S55 engines being destroyed by charge cooler failure. An upgraded all-aluminum intercooler costs approximately 800-1,500 euros installed. If engine damage has already occurred, costs escalate to 2,000-2,500 euros or more for partial rebuilds.

The oil filter housing gasket on the S55 is the same part used on the N54 and N55, and is a well-known failure point across all these engines. The rubber gasket hardens and shrinks from heat cycling, typically beginning to leak between 60,000 and 100,000 km. Oil drips onto the serpentine belt and can reach the exhaust, creating a fire risk. At an independent specialist, repair costs 400-600 euros. BMW dealers charge 700-900 euros. This is often combined with the valve cover gasket replacement to save on labor. The gasket itself is inexpensive (approximately 20-40 euros), so the cost is predominantly labor.

The S55 uses an electric water pump that can fail without warning between 80,000 and 130,000 km. Unlike a mechanical pump that whines or leaks before failing, the electric pump simply stops. The engine can overheat within minutes if the driver does not notice the warning immediately. The thermostat is electronically controlled and often replaced simultaneously. OEM water pump costs approximately 350-500 euros, and the thermostat adds 100-150 euros. At an independent specialist, total repair runs 600-900 euros. BMW dealers charge 900-1,200 euros. Preventive replacement around 100,000 km is widely recommended by S55 specialists.

The M2 Competition uses BMW's active M differential, which is known to develop seal leaks from around 25,000 km onward. Multiple owners on bimmerpost report a distinctive whine in 5th gear under full load between 60 and 100 km/h. When replaced under warranty, the replacement differential often carried a different part number, suggesting BMW revised the design. Seal replacement alone costs approximately 500-800 euros. If the differential itself needs replacement, costs rise to 1,500-2,500 euros. Regular differential oil changes every 30,000 km can help extend the life of the unit.

A common annoyance on S55 engines is a metallic ticking or rattling from the turbocharger area at idle. This is caused by wear in the wastegate actuator bushings, where play develops over time from heat cycling. The rattle is most noticeable at cold idle and typically disappears under load. While largely cosmetic and not affecting performance, it can be irritating. Replacement bushings are available as an affordable fix at approximately 150-300 euros installed. If the wastegate itself is worn and affecting boost control, a more extensive turbo repair or replacement is needed, pushing costs to 1,500-2,000 euros. Many owners choose to live with a mild rattle rather than pursue the repair.