In diesel engines there are cooling systems as to cool pistons, cylinders, liners etc, in a single or separate circuits.

Common problems to those circuits are corrosion and deposition, either of mineral seals or sludges, either of corrosion products.

Cavitation is also a main problem to diesel engines, due to meccanical / chemical factors, also known as vibration corrosion.

Growth of microorganisms is often, especially in lower temperatures circuits due to the presence of nutrients, comming from:

The engine environment (oil leaks, hydrocarbons, flue gas), system protection chemicals (containing organic and inorganic phosphorous compounds, rich in organic and inorganic nitrogen ,