This product has been superseded by: 6DA-1241B-A0-9S. Yamaha - Thermostat Cover 2 Cooling System Component 6DA-1241B-00-9S. Overview. The Yamaha Thermostat Cover 2 6DA-1241B-00-9S protects and seals the thermostat housing, helping maintain proper cooling system operation. While it may seem like a simple cover, it plays an important role in keeping the thermostat securely in place and preventing coolant leaks. If this cover becomes damaged, warped, or improperly sealed, it can lead to cooling issues or loss of pressure. Replacing it ensures your engine maintains consistent temperature control and reliable performance.. Key Features. • Protective Thermostat Housing Cover - Secures and protects the thermostat within the cooling system.. • OEM Fit Precision - Built to Yamaha specifications for proper sealing and alignment.. • Leak Prevention - Helps maintain a tight seal to prevent coolant loss.. • Durable Construction - Designed to withstand heat, pressure, and harsh marine conditions.. E