Isuzu N-Series. Manual - part 515

Engine Mechanical (4HK1-TC)   6A-165

Oil Pump

Components

Legend

1. Oil Pump Assembly
2. Spring
3. Ball
4. Split Pin

5. Driven Gear and Shaft
6. Oil Pump Body
7. Slinger

 

Removal

1. Drain out the engine oil.
2. Drain out the cooling water.
3. Remove the cylinder head cover.

Refer to “Cylinder Head Cover”.

4. Remove the rocker arm shaft assembly.

Refer to “Rocker Arm Shaft Assembly”. 

5. Remove the camshaft assembly.

Refer to “Camshaft Assembly”.

6. Remove the cylinder head assembly.

Refer to “Cylinder Head”.

7. Clutch pressure plate assembly

Refer to “Flywheel”.

8. Driven plate

Refer to “Flywheel”.

9. Remove the fuel supply pump assembly.

Refer to “Fuel Supply Pump” in Section 6C.

10. Remove the flywheel.

Refer to “Flywheel”.

11. Remove the rear oil seal of the crankshaft.

Refer to “Crankshaft Rear Oil Seal”.

12. Remove the oil pan.
13. Remove the power steering pump.
14. Remove the idle gear cover of the power steering

pump.

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6A-166   Engine Mechanical (4HK1-TC)

15. Remove the idle gear of the power steering pump.

16. Remove the flywheel housing.

• Make sure you remove the bolts shown in the

figure.

17. Remove the idle gear A.

18. Remove the oil pump assembly.

Disassembly

1. Remove the driven gear and shaft.
2. Remove the split pin.
3. Remove the spring.
4. Remove the ball.

Reassembly

1. Install the ball. 
2. Install the spring.

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Engine Mechanical (4HK1-TC)   6A-167

3. Install the split pin and fold it according to (1).

4. Apply engine oil on the driven gear and shaft and

mount them on the oil pump body.

Inspection

1. Measure the clearance between the gear and the

inner wall of the oil pump body. 

• Measure the clearance between the gear and

oil pump body using a thickness gauge.

• If the clearance between the gear and inner

wall of the body exceeds the limit, replace the
gear assembly or the driven gear assembly.

2. Measure the clearance between the gear side

surface and the upper surface of the oil pump
body.

• Measure the clearance between the gear

surface and the upper surface of the oil pump
body using the thickness gauge and square.

• If the clearance between the gear and inner

wall of the body exceeds the limit, replace the
gear assembly or the driven gear assembly.

3. Measure the clearance between the driven gear

shaft and the bush.

• Measure the outside diameter of the driven

gear shaft using a micrometer.

Clearance between the gear and inner 
wall of the body

mm (in)

Standard

0.125 – 0.220 (0.0049 – 0.0087)

Limit

0.30 (0.0118)

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Clearance between the gear side surface 
and the upper surface of the oil pump 
body

mm (in)

Standard

0.064 – 0.109 (0.0025 – 0.0043)

Limit

0.20 (0.0079)

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6A-168   Engine Mechanical (4HK1-TC)

• Measure the inside diameter of the bushes of

the oil pump body and cylinder block using the
dial gauge.

• If the clearance between the driven gear shaft

and bush exceeds the limit, replace the driven
gear assembly.

Installation

1. Install the oil pump assembly.

• Apply the liquid gasket (ThreeBond 1141E or

equivalent) as shown in the figure, mount it on
the cylinder block within one hour, and tighten it
using the specified torque.

Tighten:
Oil pump assembly to 24 N

⋅m (2.4 kg⋅m/17 lb⋅ft)

Caution:
Apply the fluid gasket such that it does not enter the
holes shown by arrows in the figure, gear, and the oil
pump body.

2. Install the idling gear A.

• Install the idling gear shaft at the position

shown in the figure and apply engine oil on the
shaft.

• Rotate the crankshaft clockwise and bring the

piston of the No.1 cylinder to the top dead
center.

Outside diameter of the driven gear shaft

mm (in)

Standard

15.989 – 16.000 (0.62949 – 0.62992)

Limit

15.900 (0.62598)

Clearance between the driven gear shaft 
and bush

mm (in)

Standard

0.04 – 0.07 (0.0016 – 0.0028)

Limit

0.20 (0.0079)

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