Cylinder head bolt long. Porsche Boxster / Cayman / 996 / 997  ❭  99610418059

Cylinder head bolt long. M10 x 230
Cylinder head bolts are essential structural fasteners used in modern engines to clamp the cylinder head, head gasket and engine block together. The OE Match bolt is the long version used in Porsche M96 and M97 engines found in various Boxster, Cayman and 911 models.
Sold individually, 24 bolts required per engine.

Fits:
Porsche 986 Boxster 2.7L / S 3.4L 2003 - 2004
Porsche 987.1 Boxster 2005 - 2008
Porsche 987C.1 Cayman 2005 - 5008
Porsche 996 C2 / C4 / C4S 2002 - 2005
Porsche 997.1 Carrera 2005 - 2008

Diagram ref no 20.

The cylinder head bolt applies the precise clamping force needed to hold the cylinder head against the engine block while compressing the head gasket. This ensures a sealed combustion chamber and prevents coolant or oil leakage. Correctly functioning head bolts are critical to maintaining engine compression, cooling efficiency and overall engine reliability.

Function
•  Engine Assembly Fastening: Secures the cylinder head to the engine block
•  Compression Seal: Maintains correct sealing of the head gasket
•  Thermal Stability: Withstands engine heat cycles and mechanical stress
•  Engine Integrity: Ensures proper combustion chamber sealing and pressure control

Cylinder head bolts experience extreme stress from combustion pressure, temperature changes and engine vibration. Over time or after repeated tightening cycles, bolts can stretch or lose their clamping strength. Replacing them during engine repairs helps maintain the correct seal between the head and block, preventing coolant leaks, compression loss or engine overheating.

Consider replacing cylinder head bolts when:
•  Rebuilding or repairing the engine
•  Replacing the head gasket
•  Engine overheating or compression loss occurs
•  The original bolts have been previously torqued or stretched

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