4M40 DIESEL ENGINE SHOP MANUAL Lubrication Caterpillar

Specifications

Structure and Operation

Lubrication System

1 Main oil gallery

2 Bypass valve

3 Bypass valve

4 Full-flow filter element

5 Bypass filter element

6 Oil cooler

7 Oil pump

8 Relief valve

9 Oil strainer

10 Regulator valve

11 Oil jet

12 Timing chain

13 Main bearing

14 Crankshaft

15 Connecting rod bearing

16 Connecting rod bushing

17 Piston

18 Check valve for oil jet

19 Idler sprocket bushing

20 Tensioner

21 Vacuum pump

22 Engine oil pressure switch

23 Camshaft bearing (No. 1)

24 Camshaft

25 Camshaft journal

26 Valve mechanism

27 Oil pan

A Orifice

Oil Pump

* This engine uses a gear-type oil pump driven by the rotation of the crankshaft transmitted through the engagement of the crankshaft gear and the oil pump gear.

* The oil pump has a relief valve (containing a steel ball and relief valve spring), which prevents excessive pressure from building up inside the lubricating system by allowing part of the engine oil to escape to the oil pan when the oil pressure exceeds a specified level.

Oil Cooler and Oil Filter

Bypass valve

* When the engine oil is cool and its viscosity is high, or when the oil cooler element becomes clogged and restricts the flow of the engine oil, the bypass valve opens to let the engine oil bypass the oil cooler and flow directly to the oil filter.

Regulator valve

* When the oil pressure in the main oil gallery exceeds the specified level, the regulator valve opens to adjust the oil pressure by allowing part of the engine oil to escape to the oil pan.

Oil Filter <Engine-mounted Type>

* This oil filter is a spin-on paper-filter type that incorporates both a bypass filter and a full-flow filter.

* A bypass valve is installed in the lower part of the oil filter. When the filter elements are clogged, this valve opens to let the engine oil bypass the filter elements and flow directly to the main oil gallery, thereby preventing seizures in the engine.

Lubrication of Engine Components

* The engine oil in the main oil gallery lubricates the engine components in the following ways.

Main bearing and connecting rod bearing

* Engine oil supplied through an oil passage in the crankshaft lubricates the big end (connecting rod bearing) of each connecting rod. Simultaneously, engine oil supplied through an oil passage in the connecting rod lubricates the connecting rod's small end.

Valve mechanism

* The engine oil flows from the main oil gallery to the oil passages in the cylinder head to lubricate every journal on the camshaft, and then returns to the oil pan.

Check valves and oil jets

* An oil jet is fitted in the lower part of the subgallery for each cylinder.

* Engine oil is sprayed out of the oil jet into the piston to cool the piston.

* Each oil jet is fitted with a check valve that opens and closes at predetermined oil pressure levels. At low engine speeds, the check valve closes to maintain the required volume of oil in the lubrication system and prevent reductions in oil pressure.

Idler shaft

Timing chain

* The engine oil from the main oil gallery is sprayed out of the oil jet onto the timing chain.

Troubleshooting

General Inspection and Adjustment

Oil Filter Replacement

Engine-mounted type

Lubricant and/or sealant

Special tools

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* Wipe up any spilled engine oil, as it can cause fires. * To avoid any risk of burns, take care not to touch the engine oil when the engine is hot.

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* Make sure not to put any engine oil on the belt when working on the oil filter. Belts soiled with oil or grease may easily slip, resulting in deteriorated performance of the cooling system. * Do not reuse the oil filter elements by washing.

[Removal]

[Installation]

* Clean the oil filter mounting surfaces of the oil cooler.

* Apply a thin coat of engine oil on the oil filter gasket.

* Screw in the oil filter by hand until the gasket touches the oil cooler. Then, tighten the filter by turning it further by five eighths (5/8) of a turn.

* After installing the oil filter, start the engine and check that there are no oil leaks.

* Remove and reinstall the oil filter if it is leaky.

* Stop the engine and check the engine oil level.

* Add engine oil if necessary.

Engine separately mounted type

Lubricant and/or sealant

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* Wipe up any spilled engine oil, as it can cause fires. * To avoid any risk of burns, take care not to touch the engine oil when the engine is hot.

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* Make sure not to put any engine oil on the belt when working on the oil filter. Belts soiled with oil or grease may easily slip, resulting in deteriorated performance of the cooling system. * Do not reuse the oil filter elements by washing.

Engine Oil Replacement

Tightening torque (Unit: N·m {kgf·m})

Lubricant and/or sealant

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* Wipe up any spilled engine oil, as it can cause fires. * To avoid any risk of burns, take care not to touch the engine oil when the engine is hot.

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* Make sure not to put any engine oil on the belt during engine oil replacement. Belts soiled with oil or grease may easily slip, resulting in deteriorated performance of the cooling system. * Do not reuse the oil filter elements by washing.

[Draining]

* Remove the filler cap.

* Remove the drain plugs of the oil pan to drain out the engine oil.

[Refilling]

* Tighten the drain plugs to the specified torque, then pour a specified amount of new engine oil into the engine.

* Stop the engine and check the engine oil level.

* Add engine oil if necessary.

Engine Oil Leak Inspection

* Visually check the engine (oil pan, oil filter, cylinder head gasket, etc.) for oil leaks. If any oil leak is found, replace the faulty part(s). (See later sections.)

Oil Pan, Oil Strainer and Oil Jet

* Disassembly sequence

1 Drain plug

2 Oil pan

3 Oil strainer

4 O-ring

5 Check valve

6 Oil jet

*a Timing gear case

*b Lower crankcase

*c Front plate

X Non-reusable parts

* Assembly sequence

Follow the disassembly sequence in reverse.

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* Make sure to tighten the check valve to the specified torque. Overtightening it can cause defective operation, resulting in engine seizure.

Tightening torque (Unit: N·m {kgf·m})

Lubricant and/or sealant

Installation procedure

Installation: Oil pan

* Clean the sealant application surfaces of each part.

* Apply a bead of sealant to each of the mating surfaces of the timing gear case, lower crankcase and front plate (at the two locations indicated the illustration).

Installation: Oil pan

* Clean the mating surfaces of each part.

* Apply a bead of sealant to the mating surface of the oil pan evenly and without any breaks.

* Mount the oil pan within three minutes of applying the sealant. Make sure that the sealant stays in place.

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* Do not start the engine less than an hour after installation. If the oil pan mounting bolts were loosened or removed, be sure to reapply sealant.

Oil Pump

* Disassembly sequence

1 Oil pump cover

2 Driven gear

3 Plug

4 Relief valve spring

5 Steel ball

6 Gear and case

7 O-ring

*a Drive gear

*b Oil pump gear

P Locating pin

X Non-reusable parts

* Assembly sequence

Follow the disassembly procedure in reverse.

Service standards (Unit: mm)

Tightening torque (Unit: N·m {kgf·m})

Lubricant and/or sealant

Inspection procedure

Inspection: Oil pump cover, driven gear, and gear and case

* Measure the clearance between each gear's shaft and the oil pump cover, as well as between each gear's shaft and the gear and case.

* If the measurements are not within the standard value range, replace the defective part(s).

Inspection: Driven gear, drive gear and gear and case

* Carry out the following inspection. Replace the oil pump if any defects are found.

(1) Sinkage of each gear from gear and case end surface

(2) Gear and case-to-tooth tip clearance for each gear

Oil Cooler <Engine-Mounted Type, Engine Separately Mounted Type>, and Oil Filter <Engine-Mounted Type>

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* Wipe up any spilled engine oil, as it can cause fires. * To avoid any risks of burns, take care not to touch the engine oil when the engine is hot.

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* Make sure not to put any engine oil on the belt when working on the oil cooler and oil filter. Belt soiled with oil or grease may easily slip, resulting in deteriorated performance of the cooling system. * Do not reuse the oil filter elements by washing.

* Removal sequence

1 Oil filter

2 Plug

3 Regulator valve spring

4 Regulator valve

5 Plug

6 Bypass valve spring

7 Bypass valve

8 Oil cooler element

9 Gasket

10 Water drain plug

11 Oil cooler body

12 O-ring

13 Gasket

14 Water separate lip

X Non-reusable parts

* Installation sequence

Follow the removal sequence in reverse.

Service standards (Unit: mm)

Tightening torque (Unit: N·m {kgf·m})

Lubricant and/or sealant

Special tools

Removal procedure

Removal: Oil filter <Engine-mounted type>

Inspection procedure

Inspection: Oil cooler element

* Plug the outlet of the oil cooler element and connect a hose to the engine oil inlet port. Then, immerse the oil cooler element in a tank of water.

* Apply an air pressure of 1.5 MPa {15 kgf/cm²} for 15 seconds through the hose, and check for any air leaks.

* Replace the element if it leaks air.

Installation procedure

Installation: Oil cooler <Engine-mounted type>

* Clean the oil filter mounting surface of the oil cooler.

* Apply a thin coat of engine oil on the oil filter gasket.

* Screw in the oil filter by hand until the gasket touches the oil cooler. Then, tighten the filter by turning further by five eighths (5/8) of a turn.

* After installing the oil filter, start the engine and check that there are no oil leaks.

* Remove and reinstall the oil filter if it is leaky.

* Stop the engine and check the engine oil level.

* Add engine oil if necessary.

Oil Filter <Engine Separately Mounted Type>

* Disassembly sequence

1 Oil filter

2 Connector

3 Plug

4 Spring

5 Relief valve

6 Plug

7 Oil filter head

X Non-reusable parts

* Assembly sequence

Follow the disassembly sequence in reverse.

Show/hide table

* Wipe up any spilled engine oil, as it can cause fires. * To avoid any risk of burns, take care not to touch the engine oil when the engine is hot.

Show/hide table

* Make sure not to put any engine oil on the belt when working on the oil cooler and oil filter. Belt soiled with oil or grease may easily slip, resulting in deteriorated performance of the cooling system. * Do not reuse the oil filter elements by washing.

Tightening torque (Unit: N·m {kgf·m})