Isuzu N-Series. Service manual - part 471

6G-4 TURBOCHARGER

8. Gasket.
9. Injection pipe.

10. Intake manifold.
11. Gasket and discard.

Installation

1. Intake manifold.

Tighten:
Intake manifold to 19 N

⋅m(1.9 kg⋅m/ 14 lb⋅ft)

2. Injection pipe

Tighten:
Fuel injector line nuts to 26 N

⋅m(2.7 kg⋅m/ 20 lb⋅ft)

3. Gasket
4. Charge air pipe.
5. Engine harness connector.
6. Bracket engine stop cable and vacuum hose.
7. Bracket accelerator cable.
8. Connecting hose.
9. Accelerator cable injection pump side.

10. PCV hose.

Turbocharger

Refer to “Statement on Cleanliness and Care” previous-
ly in this section.

Component

N6A1375E

N6A1373E

TURBOCHARGER 6G-5

Removal

1. Turbocharger air inlet pipe.
2. Turbocharger intake pipe.
3. Connecting hose.
4. Exhaust gas recirculation (EGR) pipe.
5. Heat shield bolt.
6. Water feed and drain lines.
7. Oil feed line.
8. Oil drain line.
9. Exhaust pipe to exhaust adapter nuts.

10. Exhaust adapter to turbocharger nuts.
11. Turbocharger to exhaust manifold nuts.

Caution:
The turbocharger for 4HG1-T Engine has a unit con-
struction of turbin housing and exhaust manifold.

Inspection and Repair

Caution:

• Turbocharger housing for cracks or damage.
• Gasket surfaces for damage.

• Seals and gaskets for damage.

• Turbine and compressor blades for damage or car-

bon buildup.

• Air and exhaust exit openings for oil or wetness.

• For grinding or roughness when spinning turbine

and compressor wheels by hand.

• For evidence of turbine or compressor blades con-

tacting the shroud or housing. If any of the above
conditions exist, the turbocharger must be re-
placed or repaired by an authorized repair facility.

Play in Radial Clearance
Moving the rotor in the radial clearance, measure the
play by a dial gage.

• Measure the play at several points while letting the

rotor revolve.

• Use only the flat dial gage attachment. Do not use

the pointed one.

• Attach the turbocharger and dial gage firmly.

If excessive, replace the turbocharger.

Legend

1. Water return pipe

6. Turbocharger assembly

2. Turbocharger intake pipe

7. Water feed pipe

3. Heat shield

8. Oil return pipe

4. Exhaust adapter

9. Oil feed pipe

5. Gasket

Legend

1. Air inlet pipe
2. Oil supply line
3. Turbo charger
4. Heat shield

N6A1376E

Play in radial clearance

mm (in)

Standard

Limit

0.056 — 0.127

(0.0022 — 0.0050)

0.140

(0.0055)

Legend

1. Oil outlet
2. Oil inlet

N6A1377E

6G-6 TURBOCHARGER

Play in Axial Clearance
Moving the rotor in the axial clearance, measure the
play by a dial gage.

• Measure the play at several points while letting the

rotor revolve.

• Attach the turbocharger and dial gage firmly.

If excessive, replace the turbocharger.

Operation of Waste Gate

• Disconnect hose (2) from waste gate (1), and in-

stall pressure gauge (3) as shown in the figure.

• With the engine stopped, operate the pressure

gauge pump to apply pressure to the waste gate
for check the waste gate function.

Oil Leakage Check

1. Remove the charge air pipe connecting hose to the

compressor side of the turbocharger.

2. Clean the area around the compressor wheel.
3. Remove the blow-by hose.
4. Start the engine and let idle. Rev the engine and

hold at wide open throttle (WOT) for five seconds,
then release and let idle for five seconds. Repeat
this cycle for a total of five times then let the engine
idle steady for five minutes.

5. Shut off the engine.
6. Check the compressor area for an oil stream.

Caution:

• A stream of oil indicates a possible defective turbo-

charger. If mist or spray is present, however, this is
normal and is NOT indicative of a turbocharger
problem.

7. If the turbocharger is suspect, refer to the on-vehi-

cle service procedures in this section.

Installation

1. Exhaust manifold to turbocharger.
2. New gasket and turbocharger to exhaust manifold.

Tighten:
Turbo charger to 52 N

⋅m (5.3 kg⋅m/ 38 lb⋅ft)

3. Tighten the cylinder head to turbinhousing and ex-

haust manifold to the specified torque in the nu-
merical order shown in the illustration. (4HG1-T)

Tighten:
Exhaust manifold to 34 N

⋅m (3.5 kg⋅m/ 25 lb⋅ft)

Play in axial clearance

mm (in)

Standard

Limit

0.013 — 0.097

(0.0005 — 0.0038)

0.097

(0.0038)

N6A1378E

N6A1379E

N6A1380E

TURBOCHARGER 6G-7

4. Turbocharger to exhaust adapter.

Tighten:
Exhaust adapter to 32 N

⋅m (3.3 kg⋅m/ 24 lb⋅ft)

5. Exhaust pipe to exhaust adapter.

Tighten:
Exhaust pipe to 67 N

⋅m (6.8 kg⋅m/ 49 lb⋅ft)

6. Turbocharger oil drain line.

Tighten:
Oil drain line to

• Turbocharger 9 N

⋅m (0.9 kg⋅m/ 6 lb⋅ft)

• Cylinder body 21 N

⋅m (2.1 kg⋅m/ 15 lb⋅ft)

7. Turbocharger oil supply line to turbocharger.

Tighten:
Oil supply line to 27 N

⋅m (2.8 kg⋅m/ 20 lb⋅ft)

8. Water supply and drain lines.

Tighten:
Water supply to 41 N

⋅m (4.2 kg⋅m/ 30 lb⋅ft)

9. Heat shield to exhaust adapter

10. Charge air pipe connecting hoses and clamps to

turbocharger.

11. Air inlet pipe to turbocharger.
12. Fit the connecting hose over the pipe to its project-

ing part. (4HG1-T)

13. Align connecting hose and pipe marks with each

other (4HG1-T)

N6A1381E

N6A1382E

Legend

1. Mark

N6A1383E