C11 and C13 Engines for Caterpillar Built Machines Lubrication System Caterpillar

Illustration 1	g01091921
Lubrication system schematic (1) Piston cooling jets (2) Main oil gallery in cylinder block (3) Engine pressure sensor (4) Oil flow to valve mechanism (5) Camshaft journals (6) Oil filter bypass valve (7) Main bearings (8) Signal line (9) Primary engine oil filter (10) Engine oil pump (11) Secondary oil filter (12) Oil cooler bypass valve (13) Engine oil cooler (14) Oil pan sump (15) High pressure relief valve (16) Oil pump bypass valve

Illustration 2	g01098792
Right side view of engine (9) Primary engine oil filter (10) Engine oil pump (11) Secondary oil filter (not shown) (13) Engine oil cooler

The lubrication system supplies 110 °C (230 °F) filtered oil at approximately 275 kPa (40 psi) at rated engine operating conditions. Oil pump bypass valve (18) 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 (14) maintains the engine oil temperature to 110 °C (230 °F). High pressure relief valve (17), 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). Secondary oil filter (13) 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 (5) is part of the engine protection system.

The turbocharger cartridge bearings are lubricated by the oil supply line from the main oil gallery, and the oil drain line returns the oil flow to the sump.

Oil Flow Through The Lubrication System

Illustration 3	g01609090
Oil filter base (17) Oil from engine oil cooler (18) Passage to engine oil filter (19) Filtered oil (20) Cooler bypass valve (21) Bypass valve for the engine oil pump (6) Engine oil filter bypass valve (15) High pressure relief valve (22) Oil from engine oil pump (23) Passages to secondary oil filter (24) S·O·S ports

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 (21) 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 (15) 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 680 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. The oil cooler bypass valve (20) directs the oil flow through the engine oil cooler by two different methods.

Approximately five percent of the oil flow is directed through an orificed passage that leads to the secondary oil filter (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 (6) reaches 200 kPa (29 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.

Illustration 4	g01611705
Interior of cylinder block (1) Piston cooling jets (25) Piston (26) Connecting rod

Filtered oil flows through main oil gallery (2) in the cylinder block to the following components:

• Piston cooling jets (1)

• Valve mechanism

• Camshaft bearings

• Crankshaft main bearings

• Turbocharger

The piston cooling jets provide the underside of the piston with liberal amounts of oil. The oil is used to remove heat from the piston. The oil is also used as a lubricant.

The breather allows engine blowby to escape from the crankcase. The engine blowby is discharged into the atmosphere through a hose. This prevents pressure from building up that could cause seals or gaskets to leak.