Installation above or below the waterline
The height of the cooling water injection point into the exhaust system, relative to the external waterline, is of great importance. If the water injection point is 15 cm or more above the waterline, the cooling water may be injected directly into the exhaust system. However, if the water injection point is less than 15 cm above the waterline (or even below it) there is a risk that the cooling system will siphon water through the intake, once the engine is stopped. This water will fill up the exhaust system and eventually get back into the engine cylinders via the exhaust valves. This siphon action may be prevented by having a breather hose in the cooling water line or by fitting an air vent.
To calculate the required waterlock capacity, use the following formula.