Coolant Thermostat SIERRA 118-3631

Compatible Engines

The SIERRA 118-3631 coolant thermostat is a critical component of the cooling system, designed specifically for MERCURY outboard engines ranging from 135 to 300 HP in the Verado series. It ensures precise regulation of coolant temperature, which is essential for maintaining optimal engine operating conditions and preventing overheating. Important: Due to the variety of engine configurations, compatibility must always be verified by the manufacturer's catalog number 118-3631 or the original OE number. If you have any doubts about selecting the correct part for your specific boat or engine model, we recommend contacting our customer support team for assistance.

Installation and Maintenance

Replacing the thermostat is a procedure that significantly extends the life of the power unit. Regular inspection of the thermostat condition prevents failures resulting from overheating, which can lead to costly repairs of the cylinder head or head gasket. Installation should be performed with strict cleanliness to prevent contaminants from entering the cooling system. We recommend replacing the thermostat as part of regular maintenance or upon detecting irregularities in the cooling system's operation.

• Precise temperature regulation – ensures optimal engine operating conditions.
• High durability – made from materials resistant to corrosion and high temperatures.
• Direct fit – fits perfectly into selected Mercury Verado engine models.
• Engine protection – prevents overheating and extends unit lifespan.