91307-PK2-005 O-Ring (9.5X1.5) - Overview. The 91307-PK2-005 O-Ring (9.5X1.5) is a vital sealing component used within Honda marine engine systems and select automotive applications. This part plays a crucial role in preventing fluid leaks by providing a tight seal within the engine coolant temperature sensor and related assemblies. Ensuring proper sealing allows the system to maintain correct coolant flow and engine temperature regulation, supporting reliable engine operation. The O-Ring's desi