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| Illustration 1 | g00766773 |
Lubricating system schematic (1) Piston cooling jet (2) Main oil gallery in cylinder block (3) Engine oil pressure sensor (4) Oil flow to valve mechanism (5) Camshaft journals (6) Oil filter bypass valve (7) Main bearing (Crankshaft) (8) Signal line (9) Primary oil filter (10) Engine oil pump (11) Secondary oil filter (12) Oil filter bypass valve (13) Engine oil cooler (14) Oil pan sump (15) High pressure relief valve (16) Oil pump bypass valve (17) Turbocharger | |
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| Illustration 2 | g00421818 |
Right side of engine (9) Primary oil filter (10) Engine oil pump (11) Secondary oil filter (not shown) (13) Engine oil cooler (17) Engine oil filler (18) Oil supply line to turbocharger (19) Oil drain line from turbocharger | |
The lubrication system supplies 110 °C (230 °F) filtered oil at approximately 275 kPa (40 psi) at rated engine speed. Oil pump bypass valve (16) is controlled by the engine oil manifold pressure, rather than the oil pump pressure. The engine oil manifold pressure is independent of the pressure drop that is caused by the engine oil filter and the engine oil cooler.
Oil cooler bypass valve (12) is thermostatically controlled in order to maintain engine oil to bearing temperature of 110 °C (230 °F). High pressure relief valve (15), which is located in the filter base, protects the filters and other components during cold starts. The opening pressure of the high pressure relief valve is 695 kPa (100 psi). If installed, secondary oil filter (11) is a five micron filter which filters five percent of the oil flow before returning the oil to the sump. The opening pressure of the oil filter bypass valve is 170 kPa (25 psi). Engine oil pressure sensor (3) is part of the engine protection system.
The turbocharger cartridge bearings are lubricated by oil supply line (18) from the main oil gallery, and oil drain line (19) returns the oil flow to the oil pan sump.
Oil Flow Through The Lubrication System
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| Illustration 3 | g00421838 |
Top right side view Oil flow through engine (1) Oil flow to the piston, piston cooling jets, valve mechanism, camshaft journals, crankshaft main bearings, and the turbocharger (2) Main oil gallery in cylinder block (3) Oil drains to sump (4) Cylinder block (5) Oil from engine oil cooler (6) High pressure relief valve (7) Oil from engine oil pump (8) Oil to engine oil cooler (9) Passage to primary oil filter (10) Filtered oil (11) Bypassed oil (12) Oil filter bypass valve (13) Passage to primary engine oil filter (14) Oil cooler bypass valve (15) Oil pump bypass valve (16) Oil pump bypass drain (17) Passages to secondary oil filter | |
The engine oil pump is mounted to the back of the front gear train on the lower right hand side of the engine. The engine oil pump is driven by an idler gear from the crankshaft gear. Oil is pulled from the sump through oil pump bypass valve (15) on the way to the engine oil cooler. The bypass valve controls the oil pressure from the engine oil pump. The engine oil pump can supply excess oil for the lubricating system. When this situation is present, the oil pressure increases and the bypass valve opens. The open bypass valve allows the excess oil to return to the sump.
High pressure relief valve (6) regulates high pressure in the system. The high pressure relief valve will allow the oil to return to the sump when the oil pressure reaches 695 kPa (100 psi). The oil then flows through the engine oil cooler. The engine oil cooler uses engine coolant in order to cool the oil. Oil cooler bypass valve (14) is thermostatically controlled. The oil cooler bypass valve directs the oil flow through the engine oil cooler when the oil temperature reaches 100 to 103 °C (212 to 217 °F). A failsafe activation temperature of 127 °C (260 °F), which is incorporated in the oil cooler bypass valve, will close the valve. Closing the valve directs oil flow to the engine oil cooler. The valve will remain closed if the valve fails. The oil cooler bypass valve is also activated by pressure. If the oil pressure differential across the engine oil cooler reaches 155 ± 17 kPa (22 ± 3 psi), the valve will open. Opening the valve allows the oil to bypass the engine oil cooler.
Approximately five percent of the oil flow is directed through an orificed passage that leads to secondary oil filter (17) (if equipped). The oil flows through the bypass filter and to the engine oil sump. The main oil flow now flows toward the primary engine oil filter. When the oil pressure differential across oil filter bypass valve (12) reaches 170 kPa (25 psi), the valve allows the oil flow to bypass the primary engine oil filter in order to lubricate the engine parts. The bypass valve provides immediate lubrication to the engine components when there is a restriction in the primary engine oil filter due to the following conditions:
- Cold oil with high viscosity
- Plugged primary engine oil filter
Note: Refer to Specifications, "Engine Oil Filter Base" for a cross section of the valves in the engine oil filter base.
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| Illustration 4 | g00500000 |
Interior of cylinder block (18) Piston cooling jet (19) Piston (20) Connecting rod | |
Filtered oil flows through main oil gallery (2) in the cylinder block to the following components:
- Piston cooling jets (18)
- Valve mechanism
- Camshaft bearings
- Crankshaft main bearings and rod bearings
- Turbocharger
An oil cooling chamber is formed by the following pieces: the lip forge at the top of the skirt of the piston (19) and the cavity behind the ring grooves in the crown. Oil flow from the piston cooling jet enters the cooling chamber through a drilled passage in the skirt. The oil then returns to the sump through the clearance gap between the crown and the skirt. Four holes that are drilled from the piston oil ring groove to the interior of the piston drain excess oil from the oil ring.
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| Illustration 5 | g00481403 |
Left front side of engine (21) Breather (22) Hose (23) Cylinder head | |
Breather (21) allows engine blowby to escape from the crankcase. The engine blowby is discharged into the atmosphere through hose (22). This prevents pressure from building up that could cause seals or gaskets to leak.