Sierra International 18-0844 Thermostat Cover Gasket The Sierra 18-0844 Thermostat Cover Gasket is interchangeable with the following: Mallory 9-60003, Yamaha 688-12414-A1-00. Each Sierra product meets or exceeds the original equipment part it replaces. Sierra Thermostat Cover Gasket Meets or exceeds the original equipment quality Sierra part number: 18-0844 Interchangeable with the following: Mallory 9-60003, Yamaha 688-12414-A1-00