Coolant Thermostat SIERRA 18-3644

Compatible Engines

The SIERRA 18-3644 coolant thermostat is a critical component of the cooling system, engineered for reliable performance in marine applications. It opens at a temperature of 71 °C (160 °F), ensuring optimal thermal conditions for your engine. Due to the nature of the aftermarket parts market, compatibility must be verified by comparing the catalog number 18-3644 with your engine's original OE number or technical documentation. We do not provide a specific list of brands to avoid selection errors. If you have doubts about fitting this part to your vessel, contact our store support, who will help you verify the authenticity and fitment of the part.

Installation and Operation

Replacing the thermostat is a procedure that significantly extends engine life. We recommend regular inspection of the thermostat's condition, especially before the sailing season. A blocked or malfunctioning thermostat can lead to engine overheating or prolonged warm-up times, which accelerates engine wear.

• Original SIERRA Quality – guarantees precise operation at the specified 71 °C temperature.
• Overheating Protection – effectively maintains a constant engine operating temperature.
• OE Fitment – part number 18-3644 meets engine manufacturer standards.
• Easy Installation – replacement in the standard thermostat housing without modifications.

Remember that a properly functioning cooling system is the foundation of safety on the water. By choosing the SIERRA thermostat, you invest in peace of mind and the long-term reliability of your boat.