SHAFT AS 8G1048 - Caterpillar

A centrifugal-type pump (10) is mounted on the right side of the engine on the rear face of the accessory drive housing. The water pump is gear driven. An extension of the water pump shaft through the accessory drive housing provides a convenient auxiliary drive.Water pump inlet pipe (11) is connected to the radiator outlet. Coolant from the pump (10) flows through the piping to oil cooler (9). On D399 Engines, a portion of the coolant from the piping is directed into cylinder block (8). The flow from the oil cooler is to flywheel housing (7).The flywheel housing has two separate passages. The upper passage directs the flow of coolant to the junction housing, at the left side of the flywheel housing. From the upper connection on the junction housing, part of the flow is directed through the pipe to the front core of the aftercooler (1). The crossover pipe, on the right side of the aftercooler, directs the flow through the rear core. Coolant then flows through the pipe connected to the lower connection on the junction housing where it joins with the bypassed coolant from the flywheel housing upper passage.Coolant flows back across the flywheel housing through the lower passage where the flow of coolant is divided, an equal part to each cylinder bank of the cylinder block (8). The coolant then circulates through the cylinder block, around the cylinder liners and upward through the cylinder heads (4).
FLOW OF COOLANT (SCHEMATIC)
1-Aftercooler. 2-Elbow. 3-Exhaust manifold shields. 4-Cylinder head. 5-Temperature regulator housing. 6-Radiator. 7-Flywheel housing. 8-Cylinder block. 9-Oil cooler. 10-Water pump. 11-Inlet pipe. 12-Bypass line.The coolant flows from the cylinder heads, through the elbows (2) to the exhaust manifold shields (4). The coolant circulates through the exhaust manifold shields and forward to the temperature regulator housings (5) at the front of each exhaust manifold.
FLOW OF COOLANT
1-Aftercooler. 2-Elbow. 4-Cylinder head. 5-Temperature regulator housing. 7-Flywheel housing. 8-Cylinder block. 9-Oil cooler. 10-Water pump. 11-Inlet pipe. 12-Bypass line.Regulators, positioned in each housing, control coolant flow to the radiator to regulate the temperature in the cooling system. Coolant can be directed to the radiator from either the left or right regulator housing or from both sides. When the flow is from only one side a crossover tube connects the two housings.A bypass line (12) extends from the inlet side of the temperature regulator housings to the inlet side of the water pump. When the temperature of the coolant is not high enough to open the regulators, coolant bypasses the radiator to circulate through engine, assuring quick warm-ups. A portion of the coolant flows through the bypass line at all times.Overheating
If difficulty is experienced with the engine overheating, check the following possible causes:1. Coolant Level. Insufficient water in the cooling system. If the coolant level has been allowed to fall so low that the coolant is no longer circulating, the engine should be stopped immediately and allowed to cool before adding coolant. If there is still good circulation, add makeup coolant slowly while the