MITSUBISHI ENGINES REF. 4D31 ENGINE FOR Caterpillar

5. Service Procedures

Usage:

With the oil pressure switch removed and pressure gauge installed, warm up the engine until the oil temperature reaches 70°C to 90°C.

Measure the oil pressure at idle and maximum speeds. If the measurement is below the limit, overhaul the lubricating system.

5-1 Oil Filter

5-1-1 Disassembly, Inspection and Reassembly

(1) Spin-on Type

1 Full-flow oil filter element

2 Bypass oil filter element

1 Oil pipe

2 Oil filter assembly

3 Element

4 Oil filter head

5 Regulator valve

For reassembly, reverse the order of disassembly.

NOTE:

1. For removal and installation of the spin-on type element, use Filter Wrench (special tool). Note, however, that the bypass oil filter element <D3> must be tightened by hand.

2. After the element has been installed, start the engine and check connections for oil leaks.

(2) Center Bolt Type

<DR>

1 Oil pipe

2 Oil filter assembly

3 Center bolt

4 Oil filter case

5 Spring

6 Oil filter element

7 Oil filter head

8 Regulator valve

9 Oil bypass alarm

<4DR5>

1 Oil pipe

2 Oil filter assembly

3 Center bolt

4 Oil filter case

5 Spring

6 Oil filter element

7 Oil filter head

8 Regulator valve

9 Oil bypass alarm

5-2 Oil Pump and Oil Strainer

5-2-1 Removal and Installation

<D3>

1 Oil pump

2 Oil pan

3 Oil strainer

1 Oil pump

2 Oil pan

3 Oil strainer

<DR>

1 Oil pan

2 Joint bolt

3 Oil pump assembly

5-2-2 Disassembly, Inspection and Reassembly

(1) Oil Pump <D3>

1 Oil pump cover

2 Driven gear

3 Relief valve

4 Oil pump case assembly

For reassembly, reverse the order of disassembly.

NOTE:

1. The gear is a shrink fit in the shaft of the oil pump case assembly and do not attempt to disassemble more than the illustration.

2. Before reassembly, be sure to apply engine oil to parts.

(a) Measure the drive and driven gear tooth end to oil pump case clearance. If the measurement exceeds the limit, replace the parts.

(b) Measure the difference between the drive and driven gears tooth end hight and the oil pump case depth. If the limit is exceeded, replace the parts.

(c) Measure the play in the diametral direction of the driven gear to check for driven gear to shaft clearance. If the clearance exceeds the limit, replace the parts.

(d) Measure the load at installed length of the relief valve spring. If the load is far beyond the nominal value, replace parts.

(2) Oil Pump <DR>

1 Oil strainer

2 Cover

3 Pin

4 Drive gear

5 Inner rotor

6 Shaft

7 Outer rotor

8 Oil pump case

<Disassembly sequence

1 Oil strainer

2 Pin

3 Drive gear

4 Inner rotor

5 Shaft

6 Outer rotor

7 Oil pump case

For reassembly, reverse the order of disassembly.

NOTE:

1. The pin that secures the drive gear is staked on both ends. Do not remove it unless when replacing parts.

2. An individual replacement part is not available for the outer rotor, inner rotor and shaft. When any of these parts requires replacement, replace it with an assembly.

(a) Inspection of clearance between rotors

Measure the clearance between the inner and outer rotors (tip clearance) and replace the parts if the limit is exceeded.

(b) Inspection of rotor end play

Measure the clearance between the rotor and cover and, if the limit is exceeded, replace the parts.

(c) Inspection of clearance between outer rotor and oil pump case

Measure the clearance between the outer rotor and oil pump case and, if the limit is exceeded, replace the parts.

(d) Inspection of shaft clearance

Measure the shaft O.D. and oil pump case I.D. to obtain the clearance. If the clearance exceeds the limit, replace the parts.

(e) Checking relief valve opening pressure <6DR5>

Measure the set force of the relief valve spring. If it deviates excessively from the reference value, replace the part.

5-3 Oil Cooler

5-3-1 Removal and Installation

Remove the oil cooler after removing the exhaust manifold.

1 Heat insulator

2 Water pipe

3 Oil cooler

When installing the oil cooler, align it with the oil pump mounting.

1 Oil pump stay

2 Oil pipe

3 Connector

4 Wate drain pipe

5 Oil cooler assembly

6 Oil cooler bracket

5-3-2 Disassembly, Inspection and Reassembly

1 Front cover

2 Rear cover

3 Element

4 Shell

5 Bypass valve

For reassembly, reverse the order of disassembly.

1 Oil cooler case

2 Oil cooler element

3 Bypass valve

4 Oil cooler cover

5 Oil cooler bracket

For assembly, reverse the order of disassembly.

5-3-3 Cleaning

(1) Check the oil path and bypass valve of the oil cooler element for carbon deposits and sludge formation. If contaminated, wash in a cleaning oil.

(2) If the element and cover are seriously scaled, wash with referring to 5-6 "Cleaning of Cooling System" in GROUP 14.