A prime example? Sea-Doo’s unique Closed-Loop Cooling System. Unlike competitive models that draw in water from the surrounding environment to cool their engines in an open-loop design, all Sea-Doo models since 2002 have featured a closed-loop system similar to what you’d find in a car. No corrosive salt or passage-clogging contaminants enter the engine block. Instead, it’s sealed from the surrounding environment and filled with antifreeze. In a clever bit of engineering, the craft’s ride plate acts as a heat exchanger, much like an automobile’s radiator. Antifreeze is circulated through internal passages in the ride plate, where it is cooled by the plate’s contact with the water. Coolant then returns to the engine and oil cooler, where temperature is regulated by a thermostat and temperature sensor. Closed-loop cooling is the industry standard for marine inboard diesel engines, as well as found in 50-percent of regular inboard engines for good reason. Ideal engine-operating temperature is continually maintained, maintenance is reduced and engine life extended. Performance is also improved due to more stable operating conditions.