Sierra International 18-3646 Thermostat Kit Sierra Thermostat Kit Contains: 18-2553 Thermostat Cover Gasket, 18-2834 Thermostat Cover Gasket, 18-2844 Thermostat Gasket, 18-2917 Thermostat Gasket, 18-3551 Thermostat Sierra part number: 18-3646 Interchangeable with the following: GLM 13380, Mallory 9-43151, Mercruiser 807252Q3, 807252T6