Sierra International  18-3647 Thermostat Kit Sierra Thermostat Kit Contains 18-2552 Thermostat Cover Gasket, 18-2553 Thermostat Cover Gasket, 18-2844 Thermostat Gasket, 18-2917 Thermostat Gasket, 18-3649 Thermostat, 18-7173 O-Ring Sierra part number: 18-3647 Interchangeable with the following: GLM 13101, Mallory 9-43157, Mercruiser 807252Q5, 807252T8