THERMOSTAT 8M0119207

Function and technical context

The thermostat is an essential component of the cooling system of Mercury, Mariner and MerCruiser engines that automatically regulates the temperature of the coolant. It works by opening and closing the flow of water through the radiator depending on the engine temperature, maintaining the optimal thermal regime for efficient operation of marine propulsion. A faulty thermostat causes engine overheating, reduced power, excessive fuel consumption and, in extreme cases, irreversible damage to cylinders, cylinder heads and gaskets.

When to replace this part?

Symptoms of thermostat failure include abnormal fluctuations in the temperature gauge, persistent overheating even in cold water, or conversely, difficulty in reaching normal operating temperature. It is recommended to inspect the thermostat during annual seasonal maintenance and replace it preventively every 3-4 years or depending on the manufacturer, especially after sailing in salty or turbulent waters. Replacing the thermostat preventively prevents costly mid-season breakdowns and prolongs engine life.

Compatible Mercury Mariner Engines

Equivalent manufacturer part numbers