• Speed Boat travelling fast at sea

Marine Engines – How Does the Cooling Process Work?

Unlike cars, boats have the advantage of sitting in water so the temperature of the water can be used to cool the engine and prevent it from overheating.

  • Marine Engine Installed Inside A Yacht
  • Underside of yacht with twin propellors
  • Yacht throttle

In a simple raw water cooling system, cool water from the river or sea is drawn up and passed through a filter and then cycled through the engine. This water is then passed out through the engine’s exhaust system back into the body of water. In this type of system, additional coolant is not used, and it is simply the ambient water temperature that cools the engine.

In the more sophisticated closed loop cooling system, used on larger onboard marine engines, the river or sea water works together with marine coolant that has been added to the engine’s cooling system to create the optimal cooling process.

A closed loop cooling system is particularly desirable for boats that are run on saltwater. This type of system is usually divided into two distinct sub-types. Firstly, the seawater system operates in the same way as a raw water cooling system, whereby water from the outside is drawn by pump into the closed cooling system. This water does not pass directly into the engine .

The second ’fresh water’ system circulates a coolant such as Solve-M (Solventis Marine Coolants), which is a solution of distilled water and ethylene glycol (antifreeze) inside the engine to absorb heat. This coolant is then routed to the heat exchanger where the heat that has been absorbed is transferred to the water in the seawater system and expelled. This means that no seawater is passed thought the engine itself, thus eliminating the unwelcome build-up of debris and the accumulation of deposits, which can occur when marine water comes into contact.

If you are running a boat with a closed loop cooling system, it is vital that the appropriate marine coolant is used. Solventis Marine Coolants have devised a range of marine coolants, which are compatible with the leading marine engine manufacturers’ own ranges, thus providing optimal cooling performance but without the more expensive branding.

It should also be noted that by using the appropriate marine coolant such as Solve-M the need to winterize the engine by adding antifreeze is removed, as Solve-M is dual function and will provide both frost and freeze protection.

Marine Diesel Engine