Motor coaches must provide safe and dependable transportation. Quite a variety of corrosion problems present themselves in the construction and operation of motor coaches. Some of those which concern the body are: electrolytic or galvanic corrosion between the aluminum and steel of body and frame; water vapor condensation due to respiration by passengers; abrasion and corrosion of understructure by stones and other debris thrown up by the tires, including chlorides used on the roads for de-icing and dust control; acid attack by battery electrolyte; wear and attack on stanchions, grab rails and other assist handles due to perspiration, rough hands and fabrics. Coach engines have their share of corrosion problems, too, particularly in the cooling and exhaust systems. Although numerous corrosion inhibitors do a reasonably fair job in the cooling system. Exhaust systems suffer from cold corrosion due to acid from condensation of products of combustion of the engine. However, high temperature oxidation is us...