Yanmar Pleasure Boat Marine Engine Help

Overflow bottle: ( 'fresh water' cooled engines only )

You can see this Yanmar 4LHA-STP engine is already filled with Havoline ( Texaco / Caltex ) Extended Life Coolant. Notice that the engine is cold as the fluid level is near the bottom of the bottle. As the engine warms up the pressure will increase in the cooling system until the valve in the heat exchanger cap opens and releases the coolant into the overflow bottle. It will fill to half way or more, roughly where I have drawn the red line. When the engine is stopped and it cools down, the vacuum valve in the heat exchanger cap opens, the coolant is drawn back into the engine and the level in the bottle will drop again.

Installation

• Mount the bottle so that it is less than 300mm (12 inches) above or below the heat exchanger cap level
• The connecting hose is no longer than 1 metre (3.3 feet)
• It is mounted where it can be seen and serviced easily when necessary
• On a bottle with two 'inlets' make sure the hose is connected to the pipe that goes to the bottom of the bottle. The other is an air vent and if you connect the hose to this the coolant will spray all over the engine room.