The variable valve timing adjuster sprocket bolts have a tendency to shear under high load. This is a documented issue that was also common in several other Porsche models of similar production year ranges. The valvetrain loses timing, resulting in a catastrophic engine failure which disables a vehicle. My vehicle sustained such a failure and the car immediately went into "limp mode." All the valves on one cylinder bank were bent. Other models were recalled but the Cayman and boxsters that came with the 9A1 engine were not. Porsche repaired my engine but they put the same part number that failed back into the car. There has not been an engineering revision to the part, and another failure is possible.

- Denver, CO, USA