Fuels, Lubricants, and Coolant/Engine Coolant Requirements ENGINE COOLANT REQUIREMENTS—CONTINUED 02 6 RG6263 -UN-22APR92 A—Cylinder Liner Walls B—Engine Coolant C—Vapor Bubbles Coolant solutions of ethylene glycol concentrate (antifreeze), quality water, and supplemental coolant additives (SCA’s) MUST be used year-round to protect against freezing, boil-over, liner erosion or pitting, and to provide a stable, non-corrosive environment for seals, hoses, and metal engine parts. Erosion or pitting is caused by the formation and collapse of tiny vapor bubbles in the coolant on the surface of metal parts. Over a period of time, this pitting will progress completely through the metal.
Generally, the most critical erosion occurs in the cylinder liner area of wet-sleeve, heavy-duty engines. If coolant is allowed to enter the combustion chamber, engine failure or other serious damage will result. Water pump impellers and cylinder liner walls (A) which are in contact with engine coolant (B) can be eroded or pitted unless the proper concentration and type of SCA’s are present in the coolant solution. Use of SCA’s will reduce the effects of erosion and pitting. The chemicals in the additives form a protective film on cylinder liner surface. This film acts as a barrier against collapsing vapor bubbles and also reduces the quantity of bubbles formed.
Vapor bubbles (C) are formed when piston impacts against liner ID causing walls to vibrate; sending compression waves into the coolant. RG,COOL1A -19-10OCT94 CTM42 (24MAR95) 02-6 6076 Diesel Engines—S.N. (500000— ) 160101 PN=25