Cooling and Lubrication Systems


Diesel Engine Cooling System

The tractor engine cooling system has the following components:
• Radiator
• Water pump
• Cylinder block
• Oil cooler
• Cylinder head
• Water temperature regulator (thermostat)

Coolant Flow


Coolant flow
(1) Radiator (2) Water pump (3) Cylinder block (4) Engine oil cooler (5) Cylinder head (6) Water temperature regulator (thermostat) and housing (7) Bypass for the water temperature regulator (thermostat)

The coolant flows from the bottom of the radiator (1) to the centrifugal water pump (2). The water pump (2) is installed on the front of the timing case. The water pump is driven by a gear. The gear of the fuel injection pump drives the water pump gear. The water pump forces the coolant through a passage in the timing case to the front of the cylinder block (3). The coolant enters a passage in the left side of the cylinder block (3). Some coolant enters the cylinder block. Some coolant passes over the element of the oil cooler (4). The coolant then enters the block (3). Coolant flows around the outside of the cylinders then flows from the cylinder block into the cylinder head (5).
The coolant flows forward through the cylinder head (5). The coolant then flows into the housing of the water temperature regulator (6). If the water temperature regulator (6) is closed, the coolant goes directly through a bypass (7) to the inlet side of the water pump. If the water temperature regulator is open, and the bypass is closed then the coolant flows to the top of the radiator (1).

Lubrication System

Oil pressure for the tractor engine lubrication system is provided by an engine mounted oil pump. The engine oil pump is located on the bottom of the cylinder block and within the oil pan. Lubricating oil from the oil pan flows through a strainer and a pipe to the inlet side of the engine oil pump. The engine oil pump is driven from the crankshaft through an idler gear. The engine oil pump has an inner rotor with four lobes. The inner rotor is mounted to a shaft which also carries the drive gear. The engine oil pump also has an outer annulus with five lobes. The axis of rotation of the annulus is offset relative to the rotor. The distance between the lobes of the rotor and the annulus increases on the right hand side when the rotor is rotated. The increasing space between the lobes of the rotor and the annulus causes a reduction in pressure. This reduction in oil pressure causes oil to flow from the oil pan, through the oil strainer and into the oil pump. The distance between the lobes of the rotor and annulus decreases on the left hand side when the rotor is rotated. The decreasing space between the lobes of the rotor and annulus causes oil to be pressurized. The increase in oil pressure causes oil to flow from the oil pump outlet into the engine lubrication system. The oil flows from the pump through holes in the cylinder block to a plate type oil cooler. The plate type oil cooler is located on the left hand side of the engine.

From the oil cooler, the oil returns through a drilling in the cylinder block to the filter head. The oil flows from the oil filter through a passage to the oil gallery. The oil gallery is drilled through the total length of the left side of the cylinder block. If the oil filter is on the right side of the engine, the oil flows through a pipe assembly. The pipe assembly is mounted to the lower face of the cylinder block. Lubricating oil from the oil gallery flows through passages to the main bearings of the crankshaft. The oil flows through the passages in the crankshaft to the connecting rod bearing journals. The pistons and the cylinder bores are lubricated by the splash of oil and the oil mist. Lubricating oil from the main bearings flows through passages in the cylinder block to the journals of the camshaft. Then, the oil flows from the second journal of the camshaft at a reduced pressure to the cylinder head. The oil then flows into the rocker arm bushing of the rocker arm levers. The valve stems, the valve springs and the valve lifters are lubricated by the splash and the mist of the oil. The hub of the idler gear is lubricated by oil from the oil gallery. The timing gears are lubricated by the splash of the oil. The turbocharger is lubricated by oil via a drilled passage through the cylinder block. An external line from the engine block supplies oil to the turbocharger. The oil then flows through a line to the oil pan. Piston cooling jets are installed in the engine. The piston cooling jets are supplied with the oil from the oil gallery. The piston cooling jets spray lubricating oil on the underside of the pistons in order to cool the pistons.