Coolant Thermostat SIERRA 118-3539

Compatible Engines

The SIERRA 118-3539 coolant thermostat is a critical component of the cooling system, ensuring optimal operating temperature for your marine engine. It opens at 71 °C (160 °F), which is the standard for many boat engine designs. Since official catalogs do not provide a specific list of compatible models, we recommend verifying compatibility by cross-referencing part number 118-3539 with your original equipment (OE) number or contacting our support team for assistance.

Installation and Maintenance

Proper installation is essential for engine longevity. Before replacing the thermostat, ensure the cooling system is completely drained. Pay attention to the fluid flow direction; the housing must be mounted according to the arrow on the body. Use a new gasket to prevent leaks. Regular replacement prevents overheating and extends engine life.

• SIERRA Original Quality – guarantee of durability and precision
• Standard 71 °C Opening – ideal for most engines
• Fast Response – immediate adjustment to temperature changes
• Easy Installation – no special tools required
• Corrosion Protection – resistant to saltwater damage