Cooling System Check
Skin Fitting and Sea CockValve shut. Valve spindle sheared. Blocked by weed. Plastic bag. Saltwater intake pipe. Can get blocked by fine weed and can be difficult to remove.
Remote Saltwater StrainerPoor seal allowing air into the system. Blocked filter element.
Saltwater Impeller PumpBroken impeller. Impeller slipping on its bush. Worn face plate. Defective mechanical seal. Rubber impellers mainly fail because they run dry from one of the above.
Freshwater Header TankFaulty pressure cap.
Exhaust ElbowWater injection port blocked.
Heat ExchangerBlocked or partially blocked cooling tubes. Failed cooling tubes.