SHIELD-HEAT 3176305 - Caterpillar

Illustration 1 g01366990
Cooling system schematic (1) Cylinder head (2) Outlet (3) Water temperature regulator (4) Bypass pipe (5) Water pump (6) InletThe engine has a pressure type cooling system. A pressure type cooling system gives two advantages. First, the cooling system can have safe operation at a temperature that is higher than the normal boiling point of water. The pressure type cooling system also prevents water pump cavitation. Cavitation is the sudden making of low pressure bubbles in liquids by mechanical forces. With a pressure type cooling system, it is more difficult for an air or a steam pocket to be made in the cooling system.Under normal operation, water pump (5) sends coolant into the cylinder block. Coolant travels through the cylinder block into the cylinder head (1). Coolant then travels through water outlet pipe to the housing for water temperature regulator (3). When water temperature regulator (3) is open, the coolant travels through the outlet hose to the radiator. The coolant is cooled as the coolant travels through the radiator. When the coolant gets to the bottom of the radiator, the coolant travels through the inlet hose to water pump (5) .When the engine is cold, water temperature regulator (3) is closed. The coolant does not travel to the radiator. The coolant travels from the housing for the water temperature regulator through a hose to water pump (5) .Note: Water temperature regulator (3) is an important part of the cooling system. The water temperature regulator divides coolant flow between the radiator and the bypass in order to maintain the correct temperature. Water temperature regulator (3) must be installed in order to mechanically control the system. Most of the coolant will travel through the bypass if the water temperature regulator is not installed. The engine will overheat in hot weather if water temperature regulator (3) is not installed. In cold weather, the engine will not obtain operating temperature if even small amounts of coolant travel through the radiator.