Sierra 18-3674 Thermostat Kit The Sierra 18-3674 Thermostat Kit is interchangeable with the following: GLM 13280. Contains: 18-1219 Grommet Gasket, 18-0182 Thermostat Gasket, 18-3135 Stainless Steel Bolt, 18-2546 Thermostat Gasket, 18-3567 Rubber Valve, 18-3562 Valve Cup, 18-1243 Valve Spring, 18-3563 Poppet Relief Valve, 18-3565 Retainer, 18-3543 Thermostat. Sierra Thermostat Kit Use with: 18-3543 Thermostat Sierra part number: 18-3674 Interchangeable with the following: GLM 13280