BODY AS-PISTON 1646560 - Caterpillar

This engine has a pressure type cooling system that is equipped with an expansion tank (2) and a recovery bottle (1).
Illustration 1 g01040648
(1) Recovery Bottle with a vented cap
(2) Expansion Tank with a pressure relief cap A pressure type cooling system offers two advantages:
The cooling system can operate safely at a temperature that is higher than the normal boiling point of water.
The cooling system prevents cavitation in the water pump.Cavitation is the sudden formation of low-pressure bubbles by mechanical forces in liquids. The formation of air or steam pockets is more difficult within a pressure type cooling system.The shunt line prevents cavitation by the water pump. The shunt line provides additional flow of coolant to the water pump inlet.The recovery bottle (1) provides space for expansion of the coolant volume while the engine is running. Also, the recovery bottle provides space for expansion during the warm-up cycle. The recovery bottle also provides a means for checking the coolant level.Raw Water Circuit
In many instances, a separate cooling source is used to supply coolant to the aftercooler. The coolant supply can be fresh water, or the coolant supply can be sea water. Because of the possible unknown composition of the cooling water, a special pump is needed to move the coolant through the system. Two types of pumps are available for use in the raw water circuit.
A bronze pump is used when sea water enters the system. This type of pump will resist the corrosive action of the coolant that passes through the pump.
A cast iron pump is used when the coolant is pure and noncorrosive. Raw water is drawn in through the inlet of the auxiliary water pump. The raw water will flow through the fuel cooler before the auxiliary water pump inlet if the engine is equipped with the optional fuel cooler. The raw water is forced out of the pump and into the aftercooler. The raw water flows through the aftercooler and exits at the end of the aftercooler. The raw water then travels through the marine gear cooler(if equipped), the heat exchanger, and the exhaust elbow (if equipped). The raw water is then discharged.Coolant Flow Circuit
The water pump is located on the side of the cylinder block. The water pump is gear-driven from the crankshaft.Coolant from the heat exchanger is pulled into the inlet of the water pump by impeller rotation. The coolant exits the pump directly into the engine oil cooler.After the water exits the oil cooler, the water is dispersed to three main components: cylinder block and head, turbocharger and exhaust manifold.The coolant that was directed to the cylinder block next flows into the cylinder head.The coolant exits the cylinder head and combines with the flow of coolant from the exhaust manifold and the turbocharger. The combined coolant then flows to the water temperature regulator. The coolant then flows through a deaerator in order to purge excess air to the expansion tank. The water is then returned to the heat exchanger in order to be