Sierra 18-3649 Thermostat - 160&deg; The Sierra 18-3649 Thermostat is interchangeable with the following: Crusader 97895, GLM 13100, Mallory 9-43002, Mercruiser 8M0091470, 807252T2, 8072522, 8052732, 8M0109441. Each Sierra product meets or exceeds the original equipment part it replaces. Sierra Thermostat Temperature Rating: 160 Sierra part number: 18-3649 Interchangeable with the following: Crusader 97895, GLM 13100, Mallory 9-43002, Mercruiser 8M0091470, 807252T2, 8072522, 8052732, 8M0109441