Investigation of severe corrosion of aluminum parts in stored diesel engine cooling systems

Extensive perforation of some aluminum parts caused by severe corrosion was found in the cooling systems of 250-hp (186-kw) diesel engines during long-term storage. The engines were maintained on a 2-year schedule that included replacement of the coolant-an inhibited solution of water and ethylene glycol. The failure analysis revealed three main causes of the corrosion: a) pitting corrosion initiated by chloride ions present in tap water used for the coolant preparation, of the applied inhibitors by calcium and magnesium ions present in water, and c) the development of microbiologically induced corrosion.